Effects of Cervical Vagus Nerve Stimulation on Hypothalamic Neuronal Activity' F, C. BARONE. M. J. W A Y N E R e Braht Researr
LoboratoO.. Syracttse Unil'e~wity, 601 Uttil'elwi O' Al'elltee, Syracuse N Y 1321/9
H. U. A G U I L A R - B A T U R O N I
:~ A N D R. G U E V A R A - A G U I L A R
:~
D~7~artmento de Fisloh~gia, Ftwultttd tie Medlcina, Unil'ersidttd Nachmal Aut~nlmla eh' Me.vil'o. Apartathl Postal 70250. Me.rlcr 20, D. F. ( R e c e i v e d 5 J u n e 1978)
BARONE. P. C,. M. J. WA YNBR. N, U. AGUILAR-BA'FURONIAND R, GUEVARA-AGUILAR, ls 31 ~'etl'hal itlglts tleri',. ~'ti~,lldati,m tilt h~pothalamg' neltre,lltd tltlil'gy, gRAIN REg. BULL. 4131 381-391. 1979.--The cll~cls of cervical vag~ls nerve s6mulatlun un the ncgvdy t>f56 neut,)as rCcoldcd in v ill'~OHN parts t~f tile i';ll brain were determined. Recordings were made fron nCul o9~ ; 9 [~lh the ipslhd eral and con(ralatcral bemispheres duiblg vagLl~ serve ~dlnnladon. Bolh frequency. Itl to 100 ]'17. fin0 ~ogage. I to 20 V, of 0.5 nlsec pldses were Ilpplied In tile nerve in a r~llld~31nIll~lnlle( over a 4 sec period while n~onltognf, ongoing ~ingle iletlr,~nal ~lefivity. Freq.ency icspollse l'el/uhulsbips were r ell 649; of the laleral preop6c-b~leral bypothagmllc-medi~d rtlrebrain bundle t LPA-LH-MFBI ncllrolls W~l~cbwere tested. Four types of LPA LH-MFB nClllOfla] responses wcic observed. "l'~veEilypercent of tile IICIIrOrlSillcreased hi diselmlgr freqlleney ;Is sllmtd;~tlon frequency was increased, 974 increased ill di~cbarge gequency as slbll~lb~lioll 6eq~lency w~ls decreased. 23'); tlccrei~sed [n discharge frequency as stlmuh~t~on frequel~ey was Jncle;~sed. und 14'}~decre;ised tn disebalge frequency ~ Sllmtllnllon freq.ency w:ls decre;~sed. [ncreaxing lbe sdnltlb~llon vogage alwayx cnh:meed die nlagniulde of ihe effects observed due to ~bmlging the stilnul~lie~$frequency NellrOllS observed ill seme other palts of tbo bndn were not n[recled by the same s6nltda6cln. In l~dd~(ion, cells leslcd ~1 the LPA-LH-MFB ~lrea which were previously lestetl nnd alTecled by g~lstrie distension were also affecled ~imdariy hy vagllx nerve slimubldon, Resulln :ire dlqcl~S~cd [n IClflis i~[ peripheral afferent comrol over LPA-LrhMFB ncllronal llCdvily related Io ingestive beh[tvior. Gaslnc distension Ingeslive behuvior Lateral hypolha][lllllls Medi;d forebraln bundle Single ncnrOllnl ;icdv~ly VilgllS iic~,e
T H E V A G U S nerves h a v e been implicated in Ihc c e n t l z l neural control of ingeslion [291. G~s~ric dislenslon i n h i b h s lateral h y p o t h a l a m i c ( L H ) single n e u r o n a l activity. T h e s e effects :ire e l i m i n a t e d b y v a g o t o m y a n d simtdaled by tbc electrical stimtdatlon of the a b d o m i n a l v a g u s 17[. E l e c l r i c a l activity of Ihe L H 14.51 a n d the v a g u s [44} is m o d . l a t e d by c h a n g e s in peripheral glucose levels. E l e c l r i c a l ~ t i m u l a i i o n o f the L H [6! and the vag~ls 1361 both produce e a t i n g in satiated a n i m a l s . Also. s t i m u l a l i o n of t h e dorsal v a g a l n u c l e i induces e a t i n g (261 a n d destruction of t h e s e n . c l e i results in a reduction in food i n t a k e [[51. V a g o t o m y increased the curr e n t l h r e s h o l d s for L H self-stlmulatlon a n d so-called stimulus bound e a l i n g (91. Direct c 0 ~ e n t blockage o f the v a g u s n e r v e decreases e a t i n g in food deprived cats and stimulation o f o n e or both v a g u s nerves increases e a t i n g w i l h a resubing increase in body weight [36 I. Both destrtlction of the L H {471 a n d v a g o l o m y [42[ resull in decreased food cons u m p l i o n and body weight loss in rats w h i c h is followed by a consistent a n d p r e d l c l a b l e p a t t e r n of r e c o v e r y w h e n a n i m a l s
Lulerul preop6c area
are offered m o r e pahllabte foods. In ~,ddition, botb LH lesions [3,551 a n d bilateral v a g o t o m y 1401 r e v e r s e the byperphobia and obesity caused by ventromedi~d bypotbabtmic lesions. S e v e r a l p e r m a n e n l deflcils a r e o b s e r v e d in a n i m a l s w h i c h h a v e recovered from biluleral v ~ g o t o m y and L H le sions. B u l b L H lesion 151] a n d v ~ g o t o m i z e d animals 114) e x h i b i t d e c r e a s e d fecdlng in response to 2 deoxy-D-glncose a d m i n i s t r a t i o n , T h e d i s l d b u t i o n of m e a l size and the correlation b e t w e e n mead size rind post p r a n d i a l i n t e r v a l s is dism p t e d f o l l o w i n g L H lesions [35[ a n d v a g o t o m y 1431. Reduced d r i n k i n g or adipsia occurs in L H lesioned [2I. 47,531, lateral preoptic ( L P A ) lesioned 12.131, a n d v~lgotomizcd 125,5g] a n i m a l s . B u l b v a g o t o m y 1311 a n d L H lesions 1301 e l i m i n a l e the gblcose induced suppression of e a t i n g : Body w e i g h l is decreased in both L H lesioned 1391 a n d v a g o f o m i z e d 140] a n i m a l s . In addition, v a g o l o m y and L H lesions interact to produce m u c h g r e a l e r decreases in body weight [401. T h e r e l e v a n t n e . r o a n a ~ o m y and l e u r o p b y s i o l o g y of Ibe
'Supported by a g~ant from Ihe NINCDS USPHS No. NS-13543. 2Reprlnt requests to Dr. M. J. Wayner. Brain Research Laboratory. 601 University Avenue. Syracuse NY 13210. ~Visi6ng Scientists at the Brain Research Laboratory.
Copyright o 1979 ANKHO
International Inc.--0361-9230/79/030381-04$01.60/0
BARONEETAL.
lateral preoptic-lateral h y p o t h a l a m i c - m e d i a l forebrain bundie ( L P H - L H - M F B ) region in Ihe control of spinal m o l o r reflex exeltabilfly a n d b e h a v i o r has b e e n discussed previously [49,501. Sensory inpnls from orophar~,ngeal lissue a n d the gas[roinlestlmd tract ilrc required for n o r m a l ingestive behavior. Individual n e u r o n s in the L P A - L H - M F B of the r a t m'e r/~odtdated by visceral s t i m n h d i o n associated with ]ageslion. Increases in osmotic pressnre w h i c h induce d r i n k i n g ]12. 32, 52, 541 and g a s t r o i n t e s t i n a l s t i m u l a t i o n assoclmed w k h ingestion II01 affecls the activity o f cells in this purl of t h e h y p o t h a l a m n s . An efferent L H -vagal system exists a n d is involved in the conlrol of m o t o r and h u m o r a l aspects o f digesllon II, 19, 22, 271, An afferent v a g a I - L P A - L H system w h i c h incorporates v~gal afferent i n p n l s from the gastrointestMal tl~tct 17.33,341 into the L P A - L H m o t o r conlrol syst e m related to ingestive b e h a v i o r s e e m s e q u a l l y likely. T h e r e f o r e , it seemed r e a s o n a b l e to d e t e r m i n e the effects o f v;igus nerve stimtdadon on n c n l o a S in the L P A - L H - M F B paM of the h y p o t h a l a m u s . T h e purpose of the present e x p e r i m e n t was to d e t e r m i n e fl~e effects of celwicld vllgns slinlukllion on n e u r o n s in l h e LPA-I.H-MFIB of the rat braln. N e n r o n s from o t h e r p a n s or the brain w e r e also tested to detcrln~l~e if c h a n g e s ~n netlrDnal ~lcfivily w e r e specific to ceils in Ihe L P A - L f / - M F [ L In addllion. since the v a g u s n e r v e c o m a i n s fibers which l e s p o n d l i n e a r l y to gaslrlc dislenslon, some cells wel'e observed dill" ing gaslrir tfistenslon ill addition to vagllS n e r v e s t i m u l a t i o n . [,~cs01ts indicate tha~ cervical vagt~s n e r v e s t i m n h g l o n modUhlles L P A - L f I - M F I ~ nellrOllal a c g v f l y . Both gaslric dlslen sion lind vi~gns l~el'VC stin/tllatlon pl'odHce similar effects on tbese neurons. T h e effects w e r e specific to the L P A - L H Mfi~J lind are collsistent with other data c o n c e r n i n g vag~d tPonllag o p e l ongoing b e h a v i o r and ingestion.
MI!TIIfH) A nhn,d," F e m a l e hooded ratx weigbin~ b e t w e e n 290 and 330 g w e l t selected fi'om pill' colony. Animal~ w e r e imu~ed in group cages alld w e r e kepl on a constant light-dal k cycle. T h e 12 hr light phaxe began al 060O lind w a s followed by a 12 hr d n l k philse. Room tempel'nlltrt* was nlainllPned ~11 70 ~ ~:2 ~ F /'ro~','dtt t e Rats w e r e ancs01efized will1 1.5 gtkg body w e i g h l of II['cfl~ane, ReCIIII t e m p e r a t u r e w a s c o n t i n n o u s l y m o n f l o r e d h y a themristor and nlldntained al 37" ~ I ~ C by m e a n s of a n cleelric~dly heilled h h m k e l . T m c h e o t o m i e s w e r e perforated ill all rats to I~lcillmte respiration. T h e lefl Celvical v~lglls wils dissected a w a y from the r a r l e r y . "]'he w h o l e r a g a s tlCl'VC in the mitl-cerv[c~d region at tile level of file second r~b a l o n g the Ilalchen ius~ a b o v e the Mferlor cardiac bl,~nch w a s sfinlttlaled by nleans of a bipohw silver stimtdating electrode j i l l w h i c h was lied in phlce aronnd the nerve. T h e exposed n e r v e and sfinlulafing electrode w e r e c m ' e r e d with paral~qn oil, "i'D insure thilI fl~c v.lgus was being sfinllllated, o bradycardla effect w a s verified during snrgery and a l h r e s h o h l d e t e r m i n e d 1461. H e a r t rate w a s m o l g t o r e d conlinotlsly, W h e n a change in the thresbold for v a g u s stimulation induced bradycardk~ occnrred a n d indicated possible n e r v e dtmlage, the e x p e r i m e n l wIIS t e r m i n a t e d . Only d a t a collected f i n a l animals which displayed a constant brudycardla effect ~l[ a stable threshold w e r e t~sed in the analysls. Recordings
were made from neurons in bolh the ipsilateral and contralatcral h e m i s p h e r e s d u r i n g vagus n e r v e s t i m u l a t i o n T h e polarity of r e c t a n g u l a r pulses used to s t i m u l a t e the vagus n e r v e w a s r e v e r s e d during brain cell recording. If the v~tgti$ n e r v e stimnl~tfion threshold did not cb,ange, then by r e v e r s ing the polarity the peripheral effects w e r e reduced or eliminated a n d central s t i m u l a t i o n was m a x i m i z e d . In some exp e r i m e n t s , both vagi w e r e cut at t h e cervical level in o r d e r to e i l m i n a t e p e r i p h e r a l efferent effects of the s t i m u l a t i o n . U n d e r these condilons, short l a l e n c y c h a n g e s in centred n e u n d activity had to be due to the afferenl vagal input to the brain. Following a 3 m i u baseline period of d a t a collectlon on a central neuron, a train of pulses. 0.5 m s e e in duration, w a s applied to t h e v a g u s n e r v e for a period of a sec. E a c h subsequent 4 sec pulse train w a s separated by at least 3 rain. floth freqnency a n d voltage of the v a g u s n e r v e stimt/htfiorl w e r e varied in a non-systematlc m a n n e r . T h e voltages w e r e 5, 10, 15 and 20 V. T h e frequencies w e r e 2q, 40. 60. g0 a n d 100 1-17. Sth'nuhls pal'nmeters w h l e h w e r e observed to a l l e r significantly o n g o i n g neuronal a c l i v i t y w e r e r e p e a l e d in o r d e r lu establish reliability. W h e n e v e r possible, a variety of freqnencles and vohi~ges w e r e ~lpplied to the v a g u s n e r v e in o r d e r to d e l e r m i n e f r e q u e n c y or volt~tge response relationships. A glaphical outptlt o f spikes pet" sec was tlsed In cwdhate the effecls of vagal n e r v e stimuktlion on central neuromd activity. If c h a n g e s in activity w e r e observed due ~o vagus n e r v e slimtfiafion, the nlean and standard c r r o r for l0 or 2O scc periods w e r e d e l e r m i n e d for t w o periods j u s t before each stin~nlafion a n d for a It) 9 perlods following each stimulation, f h e choice of 10 or 20 sec perlods w a s based on the duration of the effec~ and the obvious c h a n g e w h i c h occurred. Efl~'cts Ibllowing nerve sl~mulatlon w e r e considered signlfic~nt fl" the increase or decrease in :lclivfly was greilter 0ran 2 shmdard errors of i h e m e a n o f e i t h e r p r c s f i m n l a g o n baseline periods, ]13 some e x p c l l n l e n t s central n e u r o n s responsive to vngal s t i m u l a t i o n were tested for effects o f s t o m a c h distenslon. A French 30 cc p c d i a t 6 c u l M a r y l a t e x c a t h e t e r was inserted ihrongll the esophtlgtl$ into the stomach and was then tied in place al t h e level of tile lr+lcheotomy. T h e p l a c e m e n l o f the c a t h e t e r was verified +it the conclusion + f e ~ c h e x p e r l m c n t Analysis of n e u r o n a l activity c h a n g e s o v e r prolonged periods of l l m e h a v e b e e n described p r e v i o u s l y 1]0,54], Briefly, ~bllowlng n 4 m l n baselMe period, room t e m p e r a t u r e mp w a l e r w a s infused i m p Ihe balloon a~ t h e end of the g:~slric c a t h e t e r at the ra~e of L 15 n,fimln for a 10 rain period. Once filled. Ihe balloon remadned d i ~ e n d c d for 2 mln. T h e balloon was then a l l o w e d to e m p t y o v e r a 30 sec period. Spikes w e r e c o u m e d a n d gronped into 10 see bins and spikes per 10 see w e r e g r a p h i c a l l y iHtlstrated as a fimcfion o f time. A slable 4 m i n baseline was established for eacll neuron. A s~able baseline w a s defined as a period during w h i c h [he m e a n frequency in a n y of Ihe 2,1 bins (Ifl see e a c h for o total of 4 mln) did not e x c e e d • of the g r a n d m e a n for l h e 4 rain of basellne. GILStfie balloon distension was considered ~o produce a significant effect only if at least 2 post t r e a t m e n t 10 sec bin f r e q u e n c i e s differed by at leasl ~50C,~ o f the g r a n d m e a n frequency for the p r e - t r e a t m e n t baseline. A n i m a l s w e r e fixed in a stereotaxic i n s t r u m e n t w i t h the sknll horizontal, l a m b d a and bregma in the s a m e h o r i z o n t a l plane, An incision w a s m a d e in the scalp a n d the skull w a s exposed. H o l e s I - 2 m m in d i a m e t e r w e r e drilled in the calv a r i u m o v e r the L P A - L H - M F B a r e a . T h e m e n i n g e s w e r e r e m o v e d and l h e exposed b ~ d n tissue w a s covered with
HYPOTHALAMIC NEURONS AND VAGUS STIMULATION TABLE 1 EFFECTS OI r CERVICAL VAGUS NERVE STIMULA'IION ON LPA,LI-I-MFll NEURONS
Sm,rons
N
Nnnlber of Neurons Affected
LPA-LIt-MFB
35
23
Other
21
EstablishEd Frequency Related Changes Vagus Sthntdntion
Frequency Cllange~
gdnnllatioI1 frequency increased
7 ceIl~ illetellsed 8 cells dccre:lsed
Stiltnllat[Oll frequency decreased
3 cells itlc~'~lgcd 5 cells decreased
Nmle
paraffin oil. T h e holes w e r e located o v e r p r e d e t e r m i n e d re cording brain sites according Io a ral brain atlas [241. Electrode p l a c e m e n t s w e r e at i h e following coordinates, in ram, w~th the a m e r i o r coordin~lte r e l a t i v e to b r e g m a , the lateral coordinate relutive to ~he sagittal slmlre, and the v e n l r a l position m e a s u r e d from l h e SLiifaee of Ihe b n d n : A = + 1.5 Io - 2 , 5 . L - + I . 0 Io 2.0, V = 7 . 0 to 9.0. Cells lested in o t h e r bm~n a r e a s w e r e Iocaled w i t h i n Ibese a n t e r i o r and lateral planes hul w e r e m o r e dors:ll hi terms of the L P A - L H - M F B . All animals w e r e supporled by ~t clotb sling wbleb helped to m i n i m i z e e x t r a n e o u s m o v e m e n t s d u r i n g tile application of e x p e r i m e n t a l Ireatnlents. Microelectrodes w e r e tbiven by a m i c r o m a n i p n l a t o r (o the p r e d e t e r m i n e d n e u r a l sdes. E x t r a c e l h d a r a c d ~ n polen rials w e r e iecorded througb o n e barrel glas~ capillary electrodes t A - M Systems~ which bi~d been pulled to a llp dhtmet e r of 2-3/.tin and filled with a 2 M NaC] pills fast g r e e n F C F d y e sohllion h a v i n g a D C r e s i s l a n c e of 2-5 MIL Action p o l e n g a l s w e r e amplified by a high input i m p e d a n c e pre;~mplifler. d~splayed on a c o n v e n t i o n a l Teclroni• oscilloscope, lecorded on m a g n e g c lope and t h e n fed into a w i n d o w d i s c r l m m a t o r 1381 for sorting signals on Ihe basis of a m p l i t u d e and d u r a l i o m T h e formed outptlt pulses w e n t to a digital-analogue c o n v e l t e r a n d finally to a strip chart recorder for o m l i n e display of resugs. Recording sites w e r e m a r k e d by passing 15-40 IxA of n e g a t i v e DC c u r r e n t l h i o u g h the e l e c t r o d e lip for a 1O min period. The fast g r e e n F C F d y e ejected from t h e electrode tip resulted in the formation of a g r e e n spot 1481. In addition, t h e glass capillary e l e c t r o d e w a s r e t a i n e d in place until the a n i m a l s w e r e Mtracardially perfused wi~h n o r m a l saline followed by 10% formal-saline. In this w a y the electrode ~raet a n d location of the small green spot. w h i c h was approxi m a t e l y 100-200 t~m ~n d i a m e t e r , was m a d e e~lsier. Brains w e r e removed and slored in I/F/b formal-saline for a~ least 2,1 hr prior to sectioning. Frozen serial SeCllOnS. 60 /am m a d e thrOllgb the site o f t h e g r e e n spot, w e r e m o u n t e d a n d s t a i n e d witb cresyl violel for r o n d n e histological e x a m i n a t i o n . B o l h stained and u n s t a i n e d secgons w e r e e x a m i n e d u n d e r a mir ~scope a n d c o m p a r e d to plales in t h e K o n l g and Klippel rat brain a l i a s [2,11 to verify electrode tip Iocallon. In addhion, t h e ePfecls o f v a g u s n e r v e s r i m u l a l l o n o n electrocorllcographic ( E C o G ) activity w e r e d e t e r m i n e d . Single e n d e d recordings w e r e m a d e b e t w e e n 2 stainless steel skull screws each Iocaled 2 ram f r o m the m i d l l n e a n d separated b y 5 turn. One skull s c r e w w a s located I m m posterior to b r e g m a and t h e o t h e r w a s a p p r o x i m a t e l y at lambda. H e a r t r a t e was also recorded.
rESULtS Dam were eolleeled from 56 cells ill 33 animals, Frequency response relationships were established For all celia ~v'hieb were affected by vagus nerve slimnlation, F o u r types o f netil'onal responses w e i r observed. Cells (al incleased in frequency as Stilhuhllion ~l'equeney was increased: (b) increased in Ibequeney :is s t i m u l a t i o n f r e q u e n c y was de-
cre~lsed: (c) decreased in fl-cqtleney as stimul~ltion freqnency w~ls illCl•ilsed: [nld (d) dCcleased in frequency as stinltdution frequency w a s decreased. In all cases, w h e n increasing or decreasing Ibc ~limtdafion t] eqtletlcy increased ar deele;ised nelllona] f r e q u e n c y , increasing l b e slinlnlaliOn v o h a g e enhnllCed Ibe el'feel, T a b l e I is a s u n l n l a r y of these lesults, F w e n t y - d l r e e Oil[ of 35 L P A L H - M F B n e u r o n s tested w e r e affected significantly W b e n the v a g u s n e r v e stimulation w~s increased in f r e q u e n c y , 7 of t h e n e u r o n s increased in freq u e n c y a n d 8 decreased. W h e n vagus n m v e stinudatlon fieqnency w a s decreased, 3 iletlrolls increased in frequency ~111~ 5 decreased. T w e n t y - o n e n e n l o n s lested in o / h e r parts o f the brain w e r e not affected by vagus n e r v e stimulation. Figure I is a presen~arion of tbe r a w data w i d t h illustrates t h e changes in f r e q u e n c y in an L H - M F B neuron due to vagHs n e r v e ~limularion of 20 H z 15 V, 60 H z 15 V. nlld ]00 HZ ]5 V. Tbe fteqllency d e p e n d e n l i n c r e a s e c a n bc seen clearly as a function of t i m e following i h e t e r n l i n a t i o n o l s l i m u l a g o n from 0 to 6(1 sec. T h e baseline ~s indicaled from - 4 0 to 0 see prior to Ihe a d m i n i s t r a l i o n of Ihe s l i m u l a t i o n . Figure 2 is a p r e s e n l a l i o n of t h e data collecled from t h e s a m e nenron as in Fig. I. In Fig, 2, Part A. the m e a n a n d slnndard errors arc plotted for e a c h 20 sec period before a n d after v a g u s n e r v e srimulation w h l c b occurred p r i o r to 0 see. A v o h a g e related ificreasc in discharge f r e q u e n c y o e c u r l e d when sgmtdation frequency w a s held constant at 100 H z anti 5 V ( t r i a n g l e s h l0 V (squares). a n d 15 V (circles) o f s t i m u h d i o n was applled Io the vaglls n e r v e for 4 sec. T h e d a t a of Fig. I are preSEnted grapbicafly in Fig, 2, Part 13. Again. Ihe s l i m o l a l i o n freq u e n c y related c h a n g e m discharge f i e q u e n c y is demonslrated in a s i m i l a r m a n n e r . T h e results on a posterior L H - M F B n e u r o n are ilhlstraled in Fi E, 3 w h e r e Ihe data are ploHed as a flmclion of l i m e similarly to Fig. 2. Cell discharge f r e q u e n c y increased w h e n v a g a l stimuhltibn frequency w a s decreased. T h e effect occurred wit: a r e l a l i v e l y long l a t e n c y and w a s observed beg i n n i n g Ig see a R e r t h e n e r v e hud b e e n s t l m u l a t e d . Spikes p e r 10 sec periods a r e presented as a fnnclion of time for 20 sec before a n d 7O sec after (he v a g u s n e ~ e w a s sthndlated w h i c h occured prior to O. M e a n s a n d standard errors a r e platted for each 10 sec period before and a f t e r v a g u s n e r v e
384
BARONE ET AL.
lO
z
s o
Ou to -
-40
6 0 H~ t5 VOLTS
-20
o
TIME
20
IN
40
60
$ECONO$
I:IG. I . Spikes per sec presclned as a fimclltm of xhl~e in sec 40 scc before and 6~ sec after ss
of the vagns nerve for ~m L.H-M FII
ltet~rt~n Ill Ihls r;iw datm ll~e 4 see pcrlod o~ v;kgllS nerve sl{ll~n~;lliL,Dh~L~been lemn~ed from each tr:~ee and 0 sec illdlcaleS when the 5 I~fl~ll];tlion~l]s [llllle(loH'. Ronon) t nice: ge~p,~tasc ~ 4 ~ec o[ stinuiktlion at 15 V tad 20 H 7 Middle mice: Response to 4 see of slhntlhnion at [5 v lllt,] (,o H I "top trace; Response tt~ ,1 ncc of sl~mHiItllon ~n 15 V ;tad Ilk0 Ha.
s l i m n l n t i o n . W i l h vt~ltage hekl c o n s t a n l at 5 V 20 HZ ttrianglcsL 60 l l z (sqmtres). a n d 100 l t z (circles) w e r e applied to d~c v a g u s neswe fol 4 sec. T h e larget~t increase in frequency o c c u r r e d I~lr tile lowest frequency. Figure 4 is nil illnslrntlon of the results obtained on a cell located in the poslerlor M F B . T h e cell cxldbited a decrease ill rreqtlencg w h e n voltage and ffeqtlency w a s increased. Spikes p e r l0 scc periods are presented as a fimction or t i m e ft~l. 20 sec heJbre and 90 sec after the wtgtls n e r v e w a s slim~l htted. M e a n s ;tnd standalxl errors are plotted for e a c h 1O sec period belbre alld after vagtls n e r v e stlrnuhllion. W i t h voltage held constant at 5 V 20 H z (trianglesL 40 H z (squares). alld 60 ~]z (circles) w e r e applied to tile v a g u s n e r v e Ik~r4 see. T h e largest decrease in f r e q u e n c y occurred w i t h the highest I'reqnency oF slinndn~ion. Figure 5 is an illustl~ltion of the r e s u h s o b t a i n e d on a cell ideated in t h e L P A - M F B . T h i s p a r t i c u l a r cell exlfibited a d e c r e a s e i~ ikequency as voltage w a s increased and as frequellcy wils decreased. Spikes per l0 sec periods are presented :is u Function of dine for 20 see before and 4 0 sec a f t e r the 4 sec of vagus n e r v e stlmldatiolt. In Part A of Fig. 5. stlntnhltiolt with 20 V restllted in shllilar decreases w h e n 20 H I (trlanglcsl, 60 Hz (sqtlares). a n d I(Y0 H z (circles) w e r e applied to the vilgtls nerve. Part B o f Fig. 5 indieate,~ t h a i w h e n the stimu hLtion v o h a g e w a s reduced to IO V differential effects w e r e o h s e l v e d w h e n 20 H z (Iriangles), (~] HE (sql~ares). nnd ](YdH I (circles) of s t l m n l a t i o n w e r e applied to the n e r v e . T h e hlrgest decreases w e r e o b s e r v e d w i l h t h e l o w e r frequencies. T h e s e effects could not be directly related
to peripheral efferent aClivily because the nerve stimulation usually had no signlfican[ el'feel s on heart ra~e arid when both
yogi w e r e cut, e l i m i n a t i n g direct peripheral s t i m u l a t i o n , similar eflbctS were obscl~cd oil net;ronal activity, T a b l e 2 is a s u m m a r y of the restdts obtained on g cells recorded in 8 a n i m a l s which w e r e tested for both s t i m u l a t i o n of the cervicat v a g u s n e w e a n d gastric distension. T h e Incalion of e a c h cell a n d h o w h w a s affected by v a g u s s 6 m u l a t i o n a n d ga.~trlc distension are included in the table. In all eases w h e r e gastric distension resttlted in sfgnifican~ c h a n g e s in f r e q u e n c y , s 6 m u l a t i o n o f the vagtls n e r v e also resulted in a signii~cant change in f r e q u e n c y in dhe s a m e direction. O n l y o n e of the cells w h i c h responded to vagus n e r v e stimulation did not c h a n g e in response to gastric distension. O n e L H - M F B a n d I medial l e m n i s e u s cell w e r e not affected by e i t h e r ~ agtls n e r v e s t i m u l a t i o n or gastric distension. T h e first 3 ceils listed a r e also illustrated in Figs. 1 a n d 2 . 3 .'tad 5. .respectively. T h e location of e a c h cell. on the basis of histological e x a m i n t i o n , is indicated by solid c!rcles in FiRs. 6 a n d 7. T h e results of E C o G activity recorded d u r i n g v a g u s n e r v e s t i m u l a t i o n indicated t h a t c h a n g e s in n e u r a l activity could not be related to a g e n e r a l disruption o f E C o G activity. W h e n t h e a c t i v e pole of the s t l m u l a t M g e l e c t r o d e w a s proxi m a l to the b e a n . thus m a x i m i z i n g peripheral and m i n i m i z i n g central stlmutatiort, a frequency' a n d voltage related desynr of E C o G a c t i v i t y a n d i n h i b i t i o n o f h e a r t rate w e r e observed. W h e n t h e active pole w a s p r o x i m a l to the brain, thus n m x l m l z l n g c e n t r a l ~md m i n i m i z i n g p e r i p h e r a l
HYPOTHALAMIC
NEURONS
AND VAGUS
~. -JL
PAIl1" A
14
s'rIMULATION
~. 15 V O L T S -- I 0 V O L T S JL S V O L T S
385
~. --
pAR1" B
lOB Hx
~ I00 H I . = 60 Hz 15 V O L T S J- 2 0 Hz
JL
72
TO
Ns
-40
-20
0
20
40
I -40
60 TiME
IN
I --20
I 0
I 20
I 40
I 60
SECONDS
FI O, 2, Sulnc nellron a s in Fig. I Spikes p e r 20 see periods are presented as a E,notion o f time for 40 sec before a n d 60 see after 4 sec o f vag~ts ~e~,e stimulatloa, p~rl A : M e a n s a n d s t a n d a r d errocs plotted for e~cl~ 20 s e c perlod hefure ~lld :fiLer v:lg~ls n e r v e stlmldat~on whicfi occurred prior to 0 see, F r e q u e n c y w a s held const~lnt al 100 H7 a n d 5 V (trinnglesi. I0 V (sqnares). n n d 15 v (circles) Wele applied to Ihe n e ~ e . P;ir~ B: S~lrlle 3~ Jgft p l t . cxcepl vol~;ige w ~ s held const~lnt ~1( 15 V ;Lad 20 H7 (trlanglesl, 60 H7 (sqtJlH'cs). ~lnd 100 H7 (circles) were npplled to Ihe nerve.
TABLE
2
E F F E C T S O F C E R V I C A L V A G U S NEI~.VE S'/[~.IULATION A N D GAS'ri~[C I ) [ S T E N S I O N O N LPA.I~H.M FLI N E U R O N S Response to Vagus Slimulation Neurons
Vagus SOntuta~on
Frequency Clmnges
increased
increased increased decreased decreased increased increased
LIt-MFB* Pos erio LH-h FE• LH-~dFBd L I~- b,1b'13 Perifornieal MI:B LPA-MFB LH-MFB ~.tedial Lemniscus *Ifftts~rated in Figs, 1 a n d 2
decreased increased decreased increa~d increased N o Effecl No Effect tllluslrDted in Fig 3
Response Io Gastric Distension increased increased decreased decreased increased No Effe ct No Effect No Effect
$Illuslrated in Fig. 5
B A R O N E El" A L .
386
40 _-
C
100 HI 60 H= 20
5 VOLTS
HI
3o u
o
20
0
i -20
= -10
r 0
i 10
, 20
TIME
IN
, 30
~ 40
' 5.0
' 60
SECONDS
FIG 3 Spikes per 10 sec periods prescnled ;is ;L fu notion o f l i m e 20 s e t before and 70 sc~ a r i e l 4 sec o f ~;t~u5 ne rxre Sb mtlla{i~llwhich occu[retl p i l o t Io 0 sec for a posterior LH-M f:B oCIll on Mel~Ds :tad standard errors iwe plotted for e~lch I{I See period before ~lnd a f t e r the v a g u s n e r v e w~l~ M~mtJlalcd. V~.ltage was held c1A't,ttr,,I, 27: 545-553, 1970. 18. Clarke. G+ D, and J. S. Davldson. Response of dislension sensitive. regal afferent nerve end+rigs to controlled inflation of the rat stomach+ J t'lo,i,d. 256: t22-123. 1975 19 Colin-Jones. D+ G. and R L+ Himsworlh. The Ideation of lhe chemoreceptor controlling gaslric acid secretion during hypog~ycemi~LJ Physit,k 206; 397-409, 1970. 20, Davldson. J. S. Response or shlgle ~agal afferent fibers IO me chilnic;fi and chemical sfinutlation of the gastric ;rod duodenal mucosa ill eatS. Q dl t'aT' I~,y,'hoL 57: 405~416, 1972. 21. EpstehL A. N, and P. "l'eitelbaum Severe lind pe~istenl de/felts in t fi[rst produced by lateral hypot hatanlic damage. In: 7hirsr in the Regulati.m ,~jBody Water. edlted by M. J. Wayner. Oxford: Pctgatllon Prcss. 1964, pp, 39f'~410,
1973. 32. Oomnra. Y.. T. Ono. H. Ooyama and M . J. Wayner. Glucose and osmosensilive neurons in the rat hypothalamus. Nature
222: 282-284. 1969. 33 PaimuL A. S. A Mtldy ol gastric SlrelCh receptors: Their roIe in the pe6pheral mechanlsm of satiatlon of hunger zmd thirst .I. t'h3'.~toL 1261 255-270. 1954. 34. P;fintai. A S. Vagal affercm fibers. E~e,.hn Phy~i,d. bl,dog Chemw 32: 74-156. 1963. 35. Pankscpp, J, On the na~nre of feeding p:fltern~primarily in rats In: I/mlger: Btzsir ,Ue~hnnlsms .r Cll,tit..l Implications, edRed by D. Novin. W. Wyrwlcka and G. Bray. New York: Raven Press, 1976, pp. 36%381. 36. PellaloTa-Rojns, J. H., B. l];irrera-Mera and C. Kubfi Garclas. Behavioral and brain electrical changes after regal stimUhlfinn I~tpI Neur,H. 23: 378.-383. 1969. 37. Panaloza-Rojas, J. H and M. Russek. A~orexia prod~lced by dlrect-currem blockage of the VagllS nerve. Nolo.. 200: t76, 1963, 38. PelerSon. R. C., A, D. Simpson, M. J, Wayner and H. Yagl. A window discriminator for soaing elect rical signals. P/,5~iol. Behal. 4: 865-867. 1969. 39." Powley. T, L and R. E. Kersey. Relallonsh~ps of body weight to tbe Imeral bypo~halamlc syndrome. J. comf,, phJshd. Psych,d, 70: 25-36. 1970, ,I0. Powley, T. L. lind C, A OpsahL Vemromediat hypothatamlc obesity zbofished by snhdlaph~gmatlc v;igotomy. Am. J. PI...~hd. 226: 25-33. 1974, ~IL Powley, T. L. and C, A. OpsahL Autonomic components of the bypolhalamle feeding syndrome. Im H.agcr: BaMc Mech anisms aad Cli~llcaI fmplhati~ms, edited by D, Novin, W, Wyl~vieka and G. Bray. New York; Raven Press. 1976. pp. 313-525,
HYPOTHALAMIC NEURONS AND VAGUS STIMULATION 42. Rezek, M., D. A. VanderWeele and D. Novln. Stages io lhe recovery OPfeeding following vugotomy in rabbils. [~eha~. llioL 14: 75-84. 1975. 43. Sanderson. J. D. and D, A. VanderWcele. An analysis of feeding patterns in normal and vagolomiTcd rabhils. Physiol. B~,lJol 1 5 : 3 5 7 364. 1975. 44. Sudakov. K. V. and S. K. Rogacbeva. ']'he afferem and efferent activity of the gastric fibers of the ragas nerve dtlrlng fasting and after lakil~g food. Fi:i.logiche.~kr Zh.rnal US"SR 48: 306. 310. I963. ,15. Slrtin. J.. R. L. McBride. R. H. Thalmann and E, L. Van Atta Organlzalion of some brammem and ~imbic connections of the hypolhalamtbs. Ph.rnmc. Bimhem. B,,htlv. 3: Suppl. I. 49 "59. 1975. 4 6 T;ikiguwa. M. and G. J. Mogenson A study of inputs to antidromieally idenllfled neurons of tile IoetlS coertdeus. Brailt Res. 135: 2~7-230. 1977. 47. Telteihaum. P. and A, N. Epstein. The lateral hypothalamic syndrome: Recovery of feeding and drinking after iateral hypolhalamic lesions. I'~vchol R t ' , 69:7,~-90 1%2 4R. Thomas. R, C. and V. J. Wilson. Precise IoealizallOn of Ren shaw cells with a new marking technique, N,mlte 206:211-213. 1965. 4 9 Wayner. M J. Spee[f~eky ofbehav;ot~d regldatlon Physiol. Ih" hm. 12:851 869. 1974. 50. Wayner. M . J. The lateral hypothalnmus and adj~mctive drinklag. In: I',',,gse~ in Ihahe Rc.~,,~ntl,, Vol. 41. hltcgl'~uiv,, Itwmthahzmic Ar edized by D. F. Swaab and J. P. Sebade. Amslerdam: Elsevier Scientific 197,1,lip. 392-394.
51 Wayner, M J.. A. Colt, J. Millner and R. "rarlagfione. Loss of 2-decxy-D+glucose induced eaflng ~n recovered lateral rms. I'hv~h~L Behal. 7:881 8~4, 1971. 52. Wayner. M. J, and S. A. Kahan. Cenlral pathways involved during the salt arousal or drinking. Am~. N.Y. A,ad. Sol. 157: 701-722. 1969. 53, Wayner, M. J,, C. C, Louliis and F. C. Balvne. Effecls oflalernl bypotha/amic ]eslons on schedule dependent and schedule indtleed hehaviot. PhydoL Ih,hal+ 18: 5032511. 1977. 54. Weiss. C. S. ;~nd C. R. AImlL Lateral preopflc and la~era) hypotha]amic unils: In search of the osmorcceptors for thlrsl. Ph~.~;,,[ Beha~. 15; 713-722. 1975. 55. Yin. T. H. a~ld C. M. Lin. Calolle compensation ~n rats with combined leskms in lalera] and venlromedial hypothalamus. Ph~i,,I. !h,hul. 16: 46l+469. 1976, 56. Zeigler, H, P, Feedhlg behavior of the pigeOIL In: A+ha,t+t's hl tit," St.d 3 ,ff Ih'havim, Vol 7. edhed by J. RosenblalL R. A. Hinde. E. Shaw and C. Beel. New York: Academic Press. 1976. pp, 565-383. 57. Zelgler. H. P. and H. J. Karten. Cenlral tligcmlnal strncturcs and the hneral hypolhalamlc syndrome in die rat. 3"+.,m +, 1Sip: 636-638. 1974. 58, Zimmer. L. J,. L Meli?a and S. Hsiao, Effects of cervical and subdiaphragmatic vagotomy on osmotic and vtdemle thlrst. l'hy~i~d, lh,lm~, t6: 665~670, 1976.
LoboratoO.. Syracttse Unil'e~wity, 601 Uttil'elwi O' Al'elltee, Syracuse N Y 1321/9
H. U. A G U I L A R - B A T U R O N I
:~ A N D R. G U E V A R A - A G U I L A R
:~
D~7~artmento de Fisloh~gia, Ftwultttd tie Medlcina, Unil'ersidttd Nachmal Aut~nlmla eh' Me.vil'o. Apartathl Postal 70250. Me.rlcr 20, D. F. ( R e c e i v e d 5 J u n e 1978)
BARONE. P. C,. M. J. WA YNBR. N, U. AGUILAR-BA'FURONIAND R, GUEVARA-AGUILAR, ls 31 ~'etl'hal itlglts tleri',. ~'ti~,lldati,m tilt h~pothalamg' neltre,lltd tltlil'gy, gRAIN REg. BULL. 4131 381-391. 1979.--The cll~cls of cervical vag~ls nerve s6mulatlun un the ncgvdy t>f56 neut,)as rCcoldcd in v ill'~OHN parts t~f tile i';ll brain were determined. Recordings were made fron nCul o9~ ; 9 [~lh the ipslhd eral and con(ralatcral bemispheres duiblg vagLl~ serve ~dlnnladon. Bolh frequency. Itl to 100 ]'17. fin0 ~ogage. I to 20 V, of 0.5 nlsec pldses were Ilpplied In tile nerve in a r~llld~31nIll~lnlle( over a 4 sec period while n~onltognf, ongoing ~ingle iletlr,~nal ~lefivity. Freq.ency icspollse l'el/uhulsbips were r ell 649; of the laleral preop6c-b~leral bypothagmllc-medi~d rtlrebrain bundle t LPA-LH-MFBI ncllrolls W~l~cbwere tested. Four types of LPA LH-MFB nClllOfla] responses wcic observed. "l'~veEilypercent of tile IICIIrOrlSillcreased hi diselmlgr freqlleney ;Is sllmtd;~tlon frequency was increased, 974 increased ill di~cbarge gequency as slbll~lb~lioll 6eq~lency w~ls decreased. 23'); tlccrei~sed [n discharge frequency as stlmuh~t~on frequel~ey was Jncle;~sed. und 14'}~decre;ised tn disebalge frequency ~ Sllmtllnllon freq.ency w:ls decre;~sed. [ncreaxing lbe sdnltlb~llon vogage alwayx cnh:meed die nlagniulde of ihe effects observed due to ~bmlging the stilnul~lie~$frequency NellrOllS observed ill seme other palts of tbo bndn were not n[recled by the same s6nltda6cln. In l~dd~(ion, cells leslcd ~1 the LPA-LH-MFB ~lrea which were previously lestetl nnd alTecled by g~lstrie distension were also affecled ~imdariy hy vagllx nerve slimubldon, Resulln :ire dlqcl~S~cd [n IClflis i~[ peripheral afferent comrol over LPA-LrhMFB ncllronal llCdvily related Io ingestive beh[tvior. Gaslnc distension Ingeslive behuvior Lateral hypolha][lllllls Medi;d forebraln bundle Single ncnrOllnl ;icdv~ly VilgllS iic~,e
T H E V A G U S nerves h a v e been implicated in Ihc c e n t l z l neural control of ingeslion [291. G~s~ric dislenslon i n h i b h s lateral h y p o t h a l a m i c ( L H ) single n e u r o n a l activity. T h e s e effects :ire e l i m i n a t e d b y v a g o t o m y a n d simtdaled by tbc electrical stimtdatlon of the a b d o m i n a l v a g u s 17[. E l e c l r i c a l activity of Ihe L H 14.51 a n d the v a g u s [44} is m o d . l a t e d by c h a n g e s in peripheral glucose levels. E l e c l r i c a l ~ t i m u l a i i o n o f the L H [6! and the vag~ls 1361 both produce e a t i n g in satiated a n i m a l s . Also. s t i m u l a l i o n of t h e dorsal v a g a l n u c l e i induces e a t i n g (261 a n d destruction of t h e s e n . c l e i results in a reduction in food i n t a k e [[51. V a g o t o m y increased the curr e n t l h r e s h o l d s for L H self-stlmulatlon a n d so-called stimulus bound e a l i n g (91. Direct c 0 ~ e n t blockage o f the v a g u s n e r v e decreases e a t i n g in food deprived cats and stimulation o f o n e or both v a g u s nerves increases e a t i n g w i l h a resubing increase in body weight [36 I. Both destrtlction of the L H {471 a n d v a g o l o m y [42[ resull in decreased food cons u m p l i o n and body weight loss in rats w h i c h is followed by a consistent a n d p r e d l c l a b l e p a t t e r n of r e c o v e r y w h e n a n i m a l s
Lulerul preop6c area
are offered m o r e pahllabte foods. In ~,ddition, botb LH lesions [3,551 a n d bilateral v a g o t o m y 1401 r e v e r s e the byperphobia and obesity caused by ventromedi~d bypotbabtmic lesions. S e v e r a l p e r m a n e n l deflcils a r e o b s e r v e d in a n i m a l s w h i c h h a v e recovered from biluleral v ~ g o t o m y and L H le sions. B u l b L H lesion 151] a n d v ~ g o t o m i z e d animals 114) e x h i b i t d e c r e a s e d fecdlng in response to 2 deoxy-D-glncose a d m i n i s t r a t i o n , T h e d i s l d b u t i o n of m e a l size and the correlation b e t w e e n mead size rind post p r a n d i a l i n t e r v a l s is dism p t e d f o l l o w i n g L H lesions [35[ a n d v a g o t o m y 1431. Reduced d r i n k i n g or adipsia occurs in L H lesioned [2I. 47,531, lateral preoptic ( L P A ) lesioned 12.131, a n d v~lgotomizcd 125,5g] a n i m a l s . B u l b v a g o t o m y 1311 a n d L H lesions 1301 e l i m i n a l e the gblcose induced suppression of e a t i n g : Body w e i g h l is decreased in both L H lesioned 1391 a n d v a g o f o m i z e d 140] a n i m a l s . In addition, v a g o l o m y and L H lesions interact to produce m u c h g r e a l e r decreases in body weight [401. T h e r e l e v a n t n e . r o a n a ~ o m y and l e u r o p b y s i o l o g y of Ibe
'Supported by a g~ant from Ihe NINCDS USPHS No. NS-13543. 2Reprlnt requests to Dr. M. J. Wayner. Brain Research Laboratory. 601 University Avenue. Syracuse NY 13210. ~Visi6ng Scientists at the Brain Research Laboratory.
Copyright o 1979 ANKHO
International Inc.--0361-9230/79/030381-04$01.60/0
BARONEETAL.
lateral preoptic-lateral h y p o t h a l a m i c - m e d i a l forebrain bundie ( L P H - L H - M F B ) region in Ihe control of spinal m o l o r reflex exeltabilfly a n d b e h a v i o r has b e e n discussed previously [49,501. Sensory inpnls from orophar~,ngeal lissue a n d the gas[roinlestlmd tract ilrc required for n o r m a l ingestive behavior. Individual n e u r o n s in the L P A - L H - M F B of the r a t m'e r/~odtdated by visceral s t i m n h d i o n associated with ]ageslion. Increases in osmotic pressnre w h i c h induce d r i n k i n g ]12. 32, 52, 541 and g a s t r o i n t e s t i n a l s t i m u l a t i o n assoclmed w k h ingestion II01 affecls the activity o f cells in this purl of t h e h y p o t h a l a m n s . An efferent L H -vagal system exists a n d is involved in the conlrol of m o t o r and h u m o r a l aspects o f digesllon II, 19, 22, 271, An afferent v a g a I - L P A - L H system w h i c h incorporates v~gal afferent i n p n l s from the gastrointestMal tl~tct 17.33,341 into the L P A - L H m o t o r conlrol syst e m related to ingestive b e h a v i o r s e e m s e q u a l l y likely. T h e r e f o r e , it seemed r e a s o n a b l e to d e t e r m i n e the effects o f v;igus nerve stimtdadon on n c n l o a S in the L P A - L H - M F B paM of the h y p o t h a l a m u s . T h e purpose of the present e x p e r i m e n t was to d e t e r m i n e fl~e effects of celwicld vllgns slinlukllion on n e u r o n s in l h e LPA-I.H-MFIB of the rat braln. N e n r o n s from o t h e r p a n s or the brain w e r e also tested to detcrln~l~e if c h a n g e s ~n netlrDnal ~lcfivily w e r e specific to ceils in Ihe L P A - L f / - M F [ L In addllion. since the v a g u s n e r v e c o m a i n s fibers which l e s p o n d l i n e a r l y to gaslrlc dislenslon, some cells wel'e observed dill" ing gaslrir tfistenslon ill addition to vagllS n e r v e s t i m u l a t i o n . [,~cs01ts indicate tha~ cervical vagt~s n e r v e s t i m n h g l o n modUhlles L P A - L f I - M F I ~ nellrOllal a c g v f l y . Both gaslric dlslen sion lind vi~gns l~el'VC stin/tllatlon pl'odHce similar effects on tbese neurons. T h e effects w e r e specific to the L P A - L H Mfi~J lind are collsistent with other data c o n c e r n i n g vag~d tPonllag o p e l ongoing b e h a v i o r and ingestion.
MI!TIIfH) A nhn,d," F e m a l e hooded ratx weigbin~ b e t w e e n 290 and 330 g w e l t selected fi'om pill' colony. Animal~ w e r e imu~ed in group cages alld w e r e kepl on a constant light-dal k cycle. T h e 12 hr light phaxe began al 060O lind w a s followed by a 12 hr d n l k philse. Room tempel'nlltrt* was nlainllPned ~11 70 ~ ~:2 ~ F /'ro~','dtt t e Rats w e r e ancs01efized will1 1.5 gtkg body w e i g h l of II['cfl~ane, ReCIIII t e m p e r a t u r e w a s c o n t i n n o u s l y m o n f l o r e d h y a themristor and nlldntained al 37" ~ I ~ C by m e a n s of a n cleelric~dly heilled h h m k e l . T m c h e o t o m i e s w e r e perforated ill all rats to I~lcillmte respiration. T h e lefl Celvical v~lglls wils dissected a w a y from the r a r l e r y . "]'he w h o l e r a g a s tlCl'VC in the mitl-cerv[c~d region at tile level of file second r~b a l o n g the Ilalchen ius~ a b o v e the Mferlor cardiac bl,~nch w a s sfinlttlaled by nleans of a bipohw silver stimtdating electrode j i l l w h i c h was lied in phlce aronnd the nerve. T h e exposed n e r v e and sfinlulafing electrode w e r e c m ' e r e d with paral~qn oil, "i'D insure thilI fl~c v.lgus was being sfinllllated, o bradycardla effect w a s verified during snrgery and a l h r e s h o h l d e t e r m i n e d 1461. H e a r t rate w a s m o l g t o r e d conlinotlsly, W h e n a change in the thresbold for v a g u s stimulation induced bradycardk~ occnrred a n d indicated possible n e r v e dtmlage, the e x p e r i m e n l wIIS t e r m i n a t e d . Only d a t a collected f i n a l animals which displayed a constant brudycardla effect ~l[ a stable threshold w e r e t~sed in the analysls. Recordings
were made from neurons in bolh the ipsilateral and contralatcral h e m i s p h e r e s d u r i n g vagus n e r v e s t i m u l a t i o n T h e polarity of r e c t a n g u l a r pulses used to s t i m u l a t e the vagus n e r v e w a s r e v e r s e d during brain cell recording. If the v~tgti$ n e r v e stimnl~tfion threshold did not cb,ange, then by r e v e r s ing the polarity the peripheral effects w e r e reduced or eliminated a n d central s t i m u l a t i o n was m a x i m i z e d . In some exp e r i m e n t s , both vagi w e r e cut at t h e cervical level in o r d e r to e i l m i n a t e p e r i p h e r a l efferent effects of the s t i m u l a t i o n . U n d e r these condilons, short l a l e n c y c h a n g e s in centred n e u n d activity had to be due to the afferenl vagal input to the brain. Following a 3 m i u baseline period of d a t a collectlon on a central neuron, a train of pulses. 0.5 m s e e in duration, w a s applied to t h e v a g u s n e r v e for a period of a sec. E a c h subsequent 4 sec pulse train w a s separated by at least 3 rain. floth freqnency a n d voltage of the v a g u s n e r v e stimt/htfiorl w e r e varied in a non-systematlc m a n n e r . T h e voltages w e r e 5, 10, 15 and 20 V. T h e frequencies w e r e 2q, 40. 60. g0 a n d 100 1-17. Sth'nuhls pal'nmeters w h l e h w e r e observed to a l l e r significantly o n g o i n g neuronal a c l i v i t y w e r e r e p e a l e d in o r d e r lu establish reliability. W h e n e v e r possible, a variety of freqnencles and vohi~ges w e r e ~lpplied to the v a g u s n e r v e in o r d e r to d e l e r m i n e f r e q u e n c y or volt~tge response relationships. A glaphical outptlt o f spikes pet" sec was tlsed In cwdhate the effecls of vagal n e r v e stimuktlion on central neuromd activity. If c h a n g e s in activity w e r e observed due ~o vagus n e r v e slimtfiafion, the nlean and standard c r r o r for l0 or 2O scc periods w e r e d e l e r m i n e d for t w o periods j u s t before each stin~nlafion a n d for a It) 9 perlods following each stimulation, f h e choice of 10 or 20 sec perlods w a s based on the duration of the effec~ and the obvious c h a n g e w h i c h occurred. Efl~'cts Ibllowing nerve sl~mulatlon w e r e considered signlfic~nt fl" the increase or decrease in :lclivfly was greilter 0ran 2 shmdard errors of i h e m e a n o f e i t h e r p r c s f i m n l a g o n baseline periods, ]13 some e x p c l l n l e n t s central n e u r o n s responsive to vngal s t i m u l a t i o n were tested for effects o f s t o m a c h distenslon. A French 30 cc p c d i a t 6 c u l M a r y l a t e x c a t h e t e r was inserted ihrongll the esophtlgtl$ into the stomach and was then tied in place al t h e level of tile lr+lcheotomy. T h e p l a c e m e n l o f the c a t h e t e r was verified +it the conclusion + f e ~ c h e x p e r l m c n t Analysis of n e u r o n a l activity c h a n g e s o v e r prolonged periods of l l m e h a v e b e e n described p r e v i o u s l y 1]0,54], Briefly, ~bllowlng n 4 m l n baselMe period, room t e m p e r a t u r e mp w a l e r w a s infused i m p Ihe balloon a~ t h e end of the g:~slric c a t h e t e r at the ra~e of L 15 n,fimln for a 10 rain period. Once filled. Ihe balloon remadned d i ~ e n d c d for 2 mln. T h e balloon was then a l l o w e d to e m p t y o v e r a 30 sec period. Spikes w e r e c o u m e d a n d gronped into 10 see bins and spikes per 10 see w e r e g r a p h i c a l l y iHtlstrated as a fimcfion o f time. A slable 4 m i n baseline was established for eacll neuron. A s~able baseline w a s defined as a period during w h i c h [he m e a n frequency in a n y of Ihe 2,1 bins (Ifl see e a c h for o total of 4 mln) did not e x c e e d • of the g r a n d m e a n for l h e 4 rain of basellne. GILStfie balloon distension was considered ~o produce a significant effect only if at least 2 post t r e a t m e n t 10 sec bin f r e q u e n c i e s differed by at leasl ~50C,~ o f the g r a n d m e a n frequency for the p r e - t r e a t m e n t baseline. A n i m a l s w e r e fixed in a stereotaxic i n s t r u m e n t w i t h the sknll horizontal, l a m b d a and bregma in the s a m e h o r i z o n t a l plane, An incision w a s m a d e in the scalp a n d the skull w a s exposed. H o l e s I - 2 m m in d i a m e t e r w e r e drilled in the calv a r i u m o v e r the L P A - L H - M F B a r e a . T h e m e n i n g e s w e r e r e m o v e d and l h e exposed b ~ d n tissue w a s covered with
HYPOTHALAMIC NEURONS AND VAGUS STIMULATION TABLE 1 EFFECTS OI r CERVICAL VAGUS NERVE STIMULA'IION ON LPA,LI-I-MFll NEURONS
Sm,rons
N
Nnnlber of Neurons Affected
LPA-LIt-MFB
35
23
Other
21
EstablishEd Frequency Related Changes Vagus Sthntdntion
Frequency Cllange~
gdnnllatioI1 frequency increased
7 ceIl~ illetellsed 8 cells dccre:lsed
Stiltnllat[Oll frequency decreased
3 cells itlc~'~lgcd 5 cells decreased
Nmle
paraffin oil. T h e holes w e r e located o v e r p r e d e t e r m i n e d re cording brain sites according Io a ral brain atlas [241. Electrode p l a c e m e n t s w e r e at i h e following coordinates, in ram, w~th the a m e r i o r coordin~lte r e l a t i v e to b r e g m a , the lateral coordinate relutive to ~he sagittal slmlre, and the v e n l r a l position m e a s u r e d from l h e SLiifaee of Ihe b n d n : A = + 1.5 Io - 2 , 5 . L - + I . 0 Io 2.0, V = 7 . 0 to 9.0. Cells lested in o t h e r bm~n a r e a s w e r e Iocaled w i t h i n Ibese a n t e r i o r and lateral planes hul w e r e m o r e dors:ll hi terms of the L P A - L H - M F B . All animals w e r e supporled by ~t clotb sling wbleb helped to m i n i m i z e e x t r a n e o u s m o v e m e n t s d u r i n g tile application of e x p e r i m e n t a l Ireatnlents. Microelectrodes w e r e tbiven by a m i c r o m a n i p n l a t o r (o the p r e d e t e r m i n e d n e u r a l sdes. E x t r a c e l h d a r a c d ~ n polen rials w e r e iecorded througb o n e barrel glas~ capillary electrodes t A - M Systems~ which bi~d been pulled to a llp dhtmet e r of 2-3/.tin and filled with a 2 M NaC] pills fast g r e e n F C F d y e sohllion h a v i n g a D C r e s i s l a n c e of 2-5 MIL Action p o l e n g a l s w e r e amplified by a high input i m p e d a n c e pre;~mplifler. d~splayed on a c o n v e n t i o n a l Teclroni• oscilloscope, lecorded on m a g n e g c lope and t h e n fed into a w i n d o w d i s c r l m m a t o r 1381 for sorting signals on Ihe basis of a m p l i t u d e and d u r a l i o m T h e formed outptlt pulses w e n t to a digital-analogue c o n v e l t e r a n d finally to a strip chart recorder for o m l i n e display of resugs. Recording sites w e r e m a r k e d by passing 15-40 IxA of n e g a t i v e DC c u r r e n t l h i o u g h the e l e c t r o d e lip for a 1O min period. The fast g r e e n F C F d y e ejected from t h e electrode tip resulted in the formation of a g r e e n spot 1481. In addition, t h e glass capillary e l e c t r o d e w a s r e t a i n e d in place until the a n i m a l s w e r e Mtracardially perfused wi~h n o r m a l saline followed by 10% formal-saline. In this w a y the electrode ~raet a n d location of the small green spot. w h i c h was approxi m a t e l y 100-200 t~m ~n d i a m e t e r , was m a d e e~lsier. Brains w e r e removed and slored in I/F/b formal-saline for a~ least 2,1 hr prior to sectioning. Frozen serial SeCllOnS. 60 /am m a d e thrOllgb the site o f t h e g r e e n spot, w e r e m o u n t e d a n d s t a i n e d witb cresyl violel for r o n d n e histological e x a m i n a t i o n . B o l h stained and u n s t a i n e d secgons w e r e e x a m i n e d u n d e r a mir ~scope a n d c o m p a r e d to plales in t h e K o n l g and Klippel rat brain a l i a s [2,11 to verify electrode tip Iocallon. In addhion, t h e ePfecls o f v a g u s n e r v e s r i m u l a l l o n o n electrocorllcographic ( E C o G ) activity w e r e d e t e r m i n e d . Single e n d e d recordings w e r e m a d e b e t w e e n 2 stainless steel skull screws each Iocaled 2 ram f r o m the m i d l l n e a n d separated b y 5 turn. One skull s c r e w w a s located I m m posterior to b r e g m a and t h e o t h e r w a s a p p r o x i m a t e l y at lambda. H e a r t r a t e was also recorded.
rESULtS Dam were eolleeled from 56 cells ill 33 animals, Frequency response relationships were established For all celia ~v'hieb were affected by vagus nerve slimnlation, F o u r types o f netil'onal responses w e i r observed. Cells (al incleased in frequency as Stilhuhllion ~l'equeney was increased: (b) increased in Ibequeney :is s t i m u l a t i o n f r e q u e n c y was de-
cre~lsed: (c) decreased in fl-cqtleney as stimul~ltion freqnency w~ls illCl•ilsed: [nld (d) dCcleased in frequency as stinltdution frequency w a s decreased. In all cases, w h e n increasing or decreasing Ibc ~limtdafion t] eqtletlcy increased ar deele;ised nelllona] f r e q u e n c y , increasing l b e slinlnlaliOn v o h a g e enhnllCed Ibe el'feel, T a b l e I is a s u n l n l a r y of these lesults, F w e n t y - d l r e e Oil[ of 35 L P A L H - M F B n e u r o n s tested w e r e affected significantly W b e n the v a g u s n e r v e stimulation w~s increased in f r e q u e n c y , 7 of t h e n e u r o n s increased in freq u e n c y a n d 8 decreased. W h e n vagus n m v e stinudatlon fieqnency w a s decreased, 3 iletlrolls increased in frequency ~111~ 5 decreased. T w e n t y - o n e n e n l o n s lested in o / h e r parts o f the brain w e r e not affected by vagus n e r v e stimulation. Figure I is a presen~arion of tbe r a w data w i d t h illustrates t h e changes in f r e q u e n c y in an L H - M F B neuron due to vagHs n e r v e ~limularion of 20 H z 15 V, 60 H z 15 V. nlld ]00 HZ ]5 V. Tbe fteqllency d e p e n d e n l i n c r e a s e c a n bc seen clearly as a function of t i m e following i h e t e r n l i n a t i o n o l s l i m u l a g o n from 0 to 6(1 sec. T h e baseline ~s indicaled from - 4 0 to 0 see prior to Ihe a d m i n i s t r a l i o n of Ihe s l i m u l a t i o n . Figure 2 is a p r e s e n l a l i o n of t h e data collecled from t h e s a m e nenron as in Fig. I. In Fig, 2, Part A. the m e a n a n d slnndard errors arc plotted for e a c h 20 sec period before a n d after v a g u s n e r v e srimulation w h l c b occurred p r i o r to 0 see. A v o h a g e related ificreasc in discharge f r e q u e n c y o e c u r l e d when sgmtdation frequency w a s held constant at 100 H z anti 5 V ( t r i a n g l e s h l0 V (squares). a n d 15 V (circles) o f s t i m u h d i o n was applled Io the vaglls n e r v e for 4 sec. T h e d a t a of Fig. I are preSEnted grapbicafly in Fig, 2, Part 13. Again. Ihe s l i m o l a l i o n freq u e n c y related c h a n g e m discharge f i e q u e n c y is demonslrated in a s i m i l a r m a n n e r . T h e results on a posterior L H - M F B n e u r o n are ilhlstraled in Fi E, 3 w h e r e Ihe data are ploHed as a flmclion of l i m e similarly to Fig. 2. Cell discharge f r e q u e n c y increased w h e n v a g a l stimuhltibn frequency w a s decreased. T h e effect occurred wit: a r e l a l i v e l y long l a t e n c y and w a s observed beg i n n i n g Ig see a R e r t h e n e r v e hud b e e n s t l m u l a t e d . Spikes p e r 10 sec periods a r e presented as a fnnclion of time for 20 sec before a n d 7O sec after (he v a g u s n e ~ e w a s sthndlated w h i c h occured prior to O. M e a n s a n d standard errors a r e platted for each 10 sec period before and a f t e r v a g u s n e r v e
384
BARONE ET AL.
lO
z
s o
Ou to -
-40
6 0 H~ t5 VOLTS
-20
o
TIME
20
IN
40
60
$ECONO$
I:IG. I . Spikes per sec presclned as a fimclltm of xhl~e in sec 40 scc before and 6~ sec after ss
of the vagns nerve for ~m L.H-M FII
ltet~rt~n Ill Ihls r;iw datm ll~e 4 see pcrlod o~ v;kgllS nerve sl{ll~n~;lliL,Dh~L~been lemn~ed from each tr:~ee and 0 sec illdlcaleS when the 5 I~fl~ll];tlion~l]s [llllle(loH'. Ronon) t nice: ge~p,~tasc ~ 4 ~ec o[ stinuiktlion at 15 V tad 20 H 7 Middle mice: Response to 4 see of slhntlhnion at [5 v lllt,] (,o H I "top trace; Response tt~ ,1 ncc of sl~mHiItllon ~n 15 V ;tad Ilk0 Ha.
s l i m n l n t i o n . W i l h vt~ltage hekl c o n s t a n l at 5 V 20 HZ ttrianglcsL 60 l l z (sqmtres). a n d 100 l t z (circles) w e r e applied to d~c v a g u s neswe fol 4 sec. T h e larget~t increase in frequency o c c u r r e d I~lr tile lowest frequency. Figure 4 is nil illnslrntlon of the results obtained on a cell located in the poslerlor M F B . T h e cell cxldbited a decrease ill rreqtlencg w h e n voltage and ffeqtlency w a s increased. Spikes p e r l0 scc periods are presented as a fimction or t i m e ft~l. 20 sec heJbre and 90 sec after the wtgtls n e r v e w a s slim~l htted. M e a n s ;tnd standalxl errors are plotted for e a c h 1O sec period belbre alld after vagtls n e r v e stlrnuhllion. W i t h voltage held constant at 5 V 20 H z (trianglesL 40 H z (squares). alld 60 ~]z (circles) w e r e applied to tile v a g u s n e r v e Ik~r4 see. T h e largest decrease in f r e q u e n c y occurred w i t h the highest I'reqnency oF slinndn~ion. Figure 5 is an illustl~ltion of the r e s u h s o b t a i n e d on a cell ideated in t h e L P A - M F B . T h i s p a r t i c u l a r cell exlfibited a d e c r e a s e i~ ikequency as voltage w a s increased and as frequellcy wils decreased. Spikes per l0 sec periods are presented :is u Function of dine for 20 see before and 4 0 sec a f t e r the 4 sec of vagus n e r v e stlmldatiolt. In Part A of Fig. 5. stlntnhltiolt with 20 V restllted in shllilar decreases w h e n 20 H I (trlanglcsl, 60 Hz (sqtlares). a n d I(Y0 H z (circles) w e r e applied to the vilgtls nerve. Part B o f Fig. 5 indieate,~ t h a i w h e n the stimu hLtion v o h a g e w a s reduced to IO V differential effects w e r e o h s e l v e d w h e n 20 H z (Iriangles), (~] HE (sql~ares). nnd ](YdH I (circles) of s t l m n l a t i o n w e r e applied to the n e r v e . T h e hlrgest decreases w e r e o b s e r v e d w i l h t h e l o w e r frequencies. T h e s e effects could not be directly related
to peripheral efferent aClivily because the nerve stimulation usually had no signlfican[ el'feel s on heart ra~e arid when both
yogi w e r e cut, e l i m i n a t i n g direct peripheral s t i m u l a t i o n , similar eflbctS were obscl~cd oil net;ronal activity, T a b l e 2 is a s u m m a r y of the restdts obtained on g cells recorded in 8 a n i m a l s which w e r e tested for both s t i m u l a t i o n of the cervicat v a g u s n e w e a n d gastric distension. T h e Incalion of e a c h cell a n d h o w h w a s affected by v a g u s s 6 m u l a t i o n a n d ga.~trlc distension are included in the table. In all eases w h e r e gastric distension resttlted in sfgnifican~ c h a n g e s in f r e q u e n c y , s 6 m u l a t i o n o f the vagtls n e r v e also resulted in a signii~cant change in f r e q u e n c y in dhe s a m e direction. O n l y o n e of the cells w h i c h responded to vagus n e r v e stimulation did not c h a n g e in response to gastric distension. O n e L H - M F B a n d I medial l e m n i s e u s cell w e r e not affected by e i t h e r ~ agtls n e r v e s t i m u l a t i o n or gastric distension. T h e first 3 ceils listed a r e also illustrated in Figs. 1 a n d 2 . 3 .'tad 5. .respectively. T h e location of e a c h cell. on the basis of histological e x a m i n t i o n , is indicated by solid c!rcles in FiRs. 6 a n d 7. T h e results of E C o G activity recorded d u r i n g v a g u s n e r v e s t i m u l a t i o n indicated t h a t c h a n g e s in n e u r a l activity could not be related to a g e n e r a l disruption o f E C o G activity. W h e n t h e a c t i v e pole of the s t l m u l a t M g e l e c t r o d e w a s proxi m a l to the b e a n . thus m a x i m i z i n g peripheral and m i n i m i z i n g central stlmutatiort, a frequency' a n d voltage related desynr of E C o G a c t i v i t y a n d i n h i b i t i o n o f h e a r t rate w e r e observed. W h e n t h e active pole w a s p r o x i m a l to the brain, thus n m x l m l z l n g c e n t r a l ~md m i n i m i z i n g p e r i p h e r a l
HYPOTHALAMIC
NEURONS
AND VAGUS
~. -JL
PAIl1" A
14
s'rIMULATION
~. 15 V O L T S -- I 0 V O L T S JL S V O L T S
385
~. --
pAR1" B
lOB Hx
~ I00 H I . = 60 Hz 15 V O L T S J- 2 0 Hz
JL
72
TO
Ns
-40
-20
0
20
40
I -40
60 TiME
IN
I --20
I 0
I 20
I 40
I 60
SECONDS
FI O, 2, Sulnc nellron a s in Fig. I Spikes p e r 20 see periods are presented as a E,notion o f time for 40 sec before a n d 60 see after 4 sec o f vag~ts ~e~,e stimulatloa, p~rl A : M e a n s a n d s t a n d a r d errocs plotted for e~cl~ 20 s e c perlod hefure ~lld :fiLer v:lg~ls n e r v e stlmldat~on whicfi occurred prior to 0 see, F r e q u e n c y w a s held const~lnt al 100 H7 a n d 5 V (trinnglesi. I0 V (sqnares). n n d 15 v (circles) Wele applied to Ihe n e ~ e . P;ir~ B: S~lrlle 3~ Jgft p l t . cxcepl vol~;ige w ~ s held const~lnt ~1( 15 V ;Lad 20 H7 (trlanglesl, 60 H7 (sqtJlH'cs). ~lnd 100 H7 (circles) were npplled to Ihe nerve.
TABLE
2
E F F E C T S O F C E R V I C A L V A G U S NEI~.VE S'/[~.IULATION A N D GAS'ri~[C I ) [ S T E N S I O N O N LPA.I~H.M FLI N E U R O N S Response to Vagus Slimulation Neurons
Vagus SOntuta~on
Frequency Clmnges
increased
increased increased decreased decreased increased increased
LIt-MFB* Pos erio LH-h FE• LH-~dFBd L I~- b,1b'13 Perifornieal MI:B LPA-MFB LH-MFB ~.tedial Lemniscus *Ifftts~rated in Figs, 1 a n d 2
decreased increased decreased increa~d increased N o Effecl No Effect tllluslrDted in Fig 3
Response Io Gastric Distension increased increased decreased decreased increased No Effe ct No Effect No Effect
$Illuslrated in Fig. 5
B A R O N E El" A L .
386
40 _-
C
100 HI 60 H= 20
5 VOLTS
HI
3o u
o
20
0
i -20
= -10
r 0
i 10
, 20
TIME
IN
, 30
~ 40
' 5.0
' 60
SECONDS
FIG 3 Spikes per 10 sec periods prescnled ;is ;L fu notion o f l i m e 20 s e t before and 70 sc~ a r i e l 4 sec o f ~;t~u5 ne rxre Sb mtlla{i~llwhich occu[retl p i l o t Io 0 sec for a posterior LH-M f:B oCIll on Mel~Ds :tad standard errors iwe plotted for e~lch I{I See period before ~lnd a f t e r the v a g u s n e r v e w~l~ M~mtJlalcd. V~.ltage was held c1A't,ttr,,I, 27: 545-553, 1970. 18. Clarke. G+ D, and J. S. Davldson. Response of dislension sensitive. regal afferent nerve end+rigs to controlled inflation of the rat stomach+ J t'lo,i,d. 256: t22-123. 1975 19 Colin-Jones. D+ G. and R L+ Himsworlh. The Ideation of lhe chemoreceptor controlling gaslric acid secretion during hypog~ycemi~LJ Physit,k 206; 397-409, 1970. 20, Davldson. J. S. Response or shlgle ~agal afferent fibers IO me chilnic;fi and chemical sfinutlation of the gastric ;rod duodenal mucosa ill eatS. Q dl t'aT' I~,y,'hoL 57: 405~416, 1972. 21. EpstehL A. N, and P. "l'eitelbaum Severe lind pe~istenl de/felts in t fi[rst produced by lateral hypot hatanlic damage. In: 7hirsr in the Regulati.m ,~jBody Water. edlted by M. J. Wayner. Oxford: Pctgatllon Prcss. 1964, pp, 39f'~410,
1973. 32. Oomnra. Y.. T. Ono. H. Ooyama and M . J. Wayner. Glucose and osmosensilive neurons in the rat hypothalamus. Nature
222: 282-284. 1969. 33 PaimuL A. S. A Mtldy ol gastric SlrelCh receptors: Their roIe in the pe6pheral mechanlsm of satiatlon of hunger zmd thirst .I. t'h3'.~toL 1261 255-270. 1954. 34. P;fintai. A S. Vagal affercm fibers. E~e,.hn Phy~i,d. bl,dog Chemw 32: 74-156. 1963. 35. Pankscpp, J, On the na~nre of feeding p:fltern~primarily in rats In: I/mlger: Btzsir ,Ue~hnnlsms .r Cll,tit..l Implications, edRed by D. Novin. W. Wyrwlcka and G. Bray. New York: Raven Press, 1976, pp. 36%381. 36. PellaloTa-Rojns, J. H., B. l];irrera-Mera and C. Kubfi Garclas. Behavioral and brain electrical changes after regal stimUhlfinn I~tpI Neur,H. 23: 378.-383. 1969. 37. Panaloza-Rojas, J. H and M. Russek. A~orexia prod~lced by dlrect-currem blockage of the VagllS nerve. Nolo.. 200: t76, 1963, 38. PelerSon. R. C., A, D. Simpson, M. J, Wayner and H. Yagl. A window discriminator for soaing elect rical signals. P/,5~iol. Behal. 4: 865-867. 1969. 39." Powley. T, L and R. E. Kersey. Relallonsh~ps of body weight to tbe Imeral bypo~halamlc syndrome. J. comf,, phJshd. Psych,d, 70: 25-36. 1970, ,I0. Powley, T. L. lind C, A OpsahL Vemromediat hypothatamlc obesity zbofished by snhdlaph~gmatlc v;igotomy. Am. J. PI...~hd. 226: 25-33. 1974, ~IL Powley, T. L. and C, A. OpsahL Autonomic components of the bypolhalamle feeding syndrome. Im H.agcr: BaMc Mech anisms aad Cli~llcaI fmplhati~ms, edited by D, Novin, W, Wyl~vieka and G. Bray. New York; Raven Press. 1976. pp. 313-525,
HYPOTHALAMIC NEURONS AND VAGUS STIMULATION 42. Rezek, M., D. A. VanderWeele and D. Novln. Stages io lhe recovery OPfeeding following vugotomy in rabbils. [~eha~. llioL 14: 75-84. 1975. 43. Sanderson. J. D. and D, A. VanderWcele. An analysis of feeding patterns in normal and vagolomiTcd rabhils. Physiol. B~,lJol 1 5 : 3 5 7 364. 1975. 44. Sudakov. K. V. and S. K. Rogacbeva. ']'he afferem and efferent activity of the gastric fibers of the ragas nerve dtlrlng fasting and after lakil~g food. Fi:i.logiche.~kr Zh.rnal US"SR 48: 306. 310. I963. ,15. Slrtin. J.. R. L. McBride. R. H. Thalmann and E, L. Van Atta Organlzalion of some brammem and ~imbic connections of the hypolhalamtbs. Ph.rnmc. Bimhem. B,,htlv. 3: Suppl. I. 49 "59. 1975. 4 6 T;ikiguwa. M. and G. J. Mogenson A study of inputs to antidromieally idenllfled neurons of tile IoetlS coertdeus. Brailt Res. 135: 2~7-230. 1977. 47. Telteihaum. P. and A, N. Epstein. The lateral hypothalamic syndrome: Recovery of feeding and drinking after iateral hypolhalamic lesions. I'~vchol R t ' , 69:7,~-90 1%2 4R. Thomas. R, C. and V. J. Wilson. Precise IoealizallOn of Ren shaw cells with a new marking technique, N,mlte 206:211-213. 1965. 4 9 Wayner. M J. Spee[f~eky ofbehav;ot~d regldatlon Physiol. Ih" hm. 12:851 869. 1974. 50. Wayner. M . J. The lateral hypothalnmus and adj~mctive drinklag. In: I',',,gse~ in Ihahe Rc.~,,~ntl,, Vol. 41. hltcgl'~uiv,, Itwmthahzmic Ar edized by D. F. Swaab and J. P. Sebade. Amslerdam: Elsevier Scientific 197,1,lip. 392-394.
51 Wayner, M J.. A. Colt, J. Millner and R. "rarlagfione. Loss of 2-decxy-D+glucose induced eaflng ~n recovered lateral rms. I'hv~h~L Behal. 7:881 8~4, 1971. 52. Wayner. M. J, and S. A. Kahan. Cenlral pathways involved during the salt arousal or drinking. Am~. N.Y. A,ad. Sol. 157: 701-722. 1969. 53, Wayner, M. J,, C. C, Louliis and F. C. Balvne. Effecls oflalernl bypotha/amic ]eslons on schedule dependent and schedule indtleed hehaviot. PhydoL Ih,hal+ 18: 5032511. 1977. 54. Weiss. C. S. ;~nd C. R. AImlL Lateral preopflc and la~era) hypotha]amic unils: In search of the osmorcceptors for thlrsl. Ph~.~;,,[ Beha~. 15; 713-722. 1975. 55. Yin. T. H. a~ld C. M. Lin. Calolle compensation ~n rats with combined leskms in lalera] and venlromedial hypothalamus. Ph~i,,I. !h,hul. 16: 46l+469. 1976, 56. Zeigler, H, P, Feedhlg behavior of the pigeOIL In: A+ha,t+t's hl tit," St.d 3 ,ff Ih'havim, Vol 7. edhed by J. RosenblalL R. A. Hinde. E. Shaw and C. Beel. New York: Academic Press. 1976. pp, 565-383. 57. Zelgler. H. P. and H. J. Karten. Cenlral tligcmlnal strncturcs and the hneral hypolhalamlc syndrome in die rat. 3"+.,m +, 1Sip: 636-638. 1974. 58, Zimmer. L. J,. L Meli?a and S. Hsiao, Effects of cervical and subdiaphragmatic vagotomy on osmotic and vtdemle thlrst. l'hy~i~d, lh,lm~, t6: 665~670, 1976.
