THE
JOURNAL
Copyright
OF
HISTOCHEMISTRY
© 1976 by The
AND
Histochemical
Vol.
CYTOCHEMISTRY
Society,
Inc.
Letters
LEVELS
OF
PUTATIVE
to the
2-.ig
samples
of
tissue
dissected
from
Editor
TRANSMITTER AMINO GUINEA PIG COCHLEA’
Although considerable effort has been directed toward establishing acetyichobine as a chemical transmitter at the obivocochlear synapses, investigation of the robe of other putative chemical transmitters in cochbear function is in a preliminary’ stage (7, 10). In order to provide some basic information relevant to the possible robe of amino acids as transmitters in the cochlea, we have measured levels of ‘y-aminobutyrate (GABA), glycine, glutamate and aspartate in 0.2- to a total
24, No, 2, pp. 468-472, 1976 Printed in LS.A.
ACIDS
IN
THE
dry weight for inner hair cell region. The data for the other cochhear regions had standard errors similar to those for organ of Corti. Our average level of 1.8 mmoles GABA/kg dry weight in organ of Corti compares with levels of 2.3-9.7 mmoles GABA/kg wet weight reported for various regions of the guinea pig brain (15) and bevels of 2-14 mmoles GABA/kg dry’ weight which we found for regions of a rat cochbear nucleus frozen immediately at death. Thalmann et al. (22) found even lower bevels of GABA in organ of Corti than we did, and Tachibana and Kuriyama (21) did not detect any. We did not find higher GABA bevels in spiral gangbion than in other cochlear regions, as Tachibana and Kuriyama did. The bow GABA bevels in organ of Corti and the finding of similar levels in cochbear regions which do not contain any part of the obivocochlear system (e.g., stria vascubaris and Reissner’s membrane) do not
of six
freeze-dried cochbeas, each obtained from a separate guinea pig. The sampling methods have been described previously ( 14). Samples were obtained from the various cochbear regions without attempting to sample systematically the entirety of each region or check the exact contents of each sample. The organ of Corti samples were split into inner and outer hair cell regions by a cut through the tunnel. The basilar tunnel fibers traveling at the floor of the tunnel were not in the organ of Corti samples but rather were likely to be in the basilar membrane samples. The assay procedures, by which all four of these amino acids were measured for each individual freeze-dried sample in oil wells, will be presented elsewhere’ but are based on published methods (1, 2, 4, 17). Low bevels of GABA were found in all cochlear regions examined, whereas levels of glycine were high for all regions (Fig. 1). Glutamate and aspartate levels were higher in the organ of Corti than in any other cochlear region. Additionally, there were gradients of aspartate bevels along the cochbear length of both inner and outer hair cehl regions. It should be mentioned that, since we were measuring all four amino acids in each sample and since the levels of all except GABA were quite high, the samples used did not provide amounts of GABA far above the bower limit of sensitivity of our GABA assay. The GABA bevels measured in individual organ of Corti samples had a considerable range: between -0.52 and +3.52 mmoles/kg dry weight for outer hair cell region and between --0.19 and +4.87 mmoles/kg
support
the
suggestion
of Richrath
et al.
(18)
that
the
efferent system of the organ of Corti contains a high concentration of GABA. This suggestion was based on the localization within the efferent system of tritiated GABA perfused through the cochlea. Further evidence against this possibility is our finding, to be reported in more detail elsewhere,3 that the part of the vestibubar nerve root where the olivocochbear bundles travel has bow GABA bevels weight). Evidently, cells may GABA without themselves Since the cochlear hair ble
proportion
of organ
for GABA are especially’ Flock and Lam (8) that transmitter
at
the
hair
(1-2 be
mmobes/kg dry abbe to take up
containing cells comprise of Corti
much GABA. a considera-
samples.
our
results
contrary’ to the suggestion GABA may be the chemical cell-to-auditory
nerve
of
syn-
apses. Their suggestion is based on in vitro synthesis of GABA by lateral line organs but does not consider the rates of synthesis in the context of those of other tissues. This is an important consideration, since neural tissues may contain small amounts of glutamic acid decarboxylase activity without either containing much GABA (11, 12) or releasing GABA as a transmitter (16). The approach used by Flock and Lam is similar to that (13) which bed to the suggestion. since indicated to be unlikely (19), that turtle photoreceptor cells may’ be chohinergic. The glycine levels for organ of Corti are similar to
‘These studies were supported by the American Cancer Society through Research Grant BC4Q, the National Institutes of Health through Research Grants NSO8000 and NS08862, and a National Institutes of Health Postdoctoral Fellowship to D. A. G. (F02NS52,35402). 2 Berger 5,1, CarterJA, Lowry OH: In preparation.
Godfrey Matschinsky
DA, Carter JA, Berger FM: In preparation.
468
Downloaded from jhc.sagepub.com by guest on March 10, 2015
SJ,
Lowry
OH,
LETFERS
TO THE
469
EDITOR
O’I-Amisobutyrats
80
luGlycini #{163} #{149} Glut.nats
80
6.taIs
70 60
150
50
40 30 20
20
----
10 7-
COCHLEAR HAIR
l0 I TURN CELLS
I FOR
RM OTHER
SV aM COCHLEAR
SG AN TISSUES
Ftc.. 1. Levels of amino acids for various regions of guinea pig cochlea. standard errors based on average values for individual cochbeas are presented regions of each cochbear turn. (For y-aminobutyrate, the standard errors Except for -y-aminobutyrate in the inner hair cell region of turn III, which point is based on samples from three to six cochbeas. Samples were obtained regions of all four cochlear turns for three cochleas in the case of aspartate,
For the organ of Corti, means and for inner (I) and outer (0) hair cell fall within the size of the circles.) is based on two cochbeas, each data from both inner and outer hair cell two for the other amino acids.
For the other cochbear regions, data from the various turns are grouped. Means are presented, based on samples from two to five cochbeas. RM, Reissner’s membrane: SV, stria vascularis; BM, basilar membrane; SG, spiral ganglion; AN, auditory nerve central to spiral ganglion. For comparison with the cochlear results, bevels of the four amino acids measured in an extract of a piece of frontal cortex removed from an anesthetized cat and immediately frozen (values converted to an equivalent dry weight basis by multiplying by five) were 3.8 mmoles GABA, 3.5 mmobes glycine, 47 mmoles glutamate and 12 mmoles aspartate/kg equivalent dry weight. those
reported
glycine
has
(9).
That
other
that
hand,
stria
high
role
raise here
to contain
glycine
as
in
bevels
of glycine
It is of interest reported
some
doubts
in the
cochlea.
that
horse
to
the
acids
(3).
amino
acid
bevels
resulting
fluids
during
determined.
cochlear
The
regions
not bathed
ble
that
central which
the to we
cochlear
organ
found and
higher of
other
Corti
bevels
spiral
most
of
has
nerve
nerve
were
bevels
of
glutamate
than
in
other
as it enters
the
less
region,
times
levels
cochbear
We
thank
Dr.
dissecting
the
McDougab,
Jr.
script, script
those
aspartate regions
J.
J.
Krzanowski,
freeze-dried for
Jr.
for
cochbeas,
critical
Mrs. Barbara and Anne Fuller
evaluation
Pordy Dillon
help
Dr. of
for typing for drawing
the
with D.
B.
manu-
the manuthe figure.
the
LITERATURE
of GABA,
similar. and
ACKNOWLEDc.MENTS
the
nerve,
It is remarkafour
suggest the involvement of these amino acids in cochbear synaptic transmission. Both were reported to “act bike transmitters” at the synapses of medium electroreceptors of the acousticolaterahis system in a mormyrid fish (20). However, our data do not permit conclusions about distribution of glutamate or aspartate among the various types of cells contained in the organ of Corti samples. The significance of the aspartate gradient in organ of Corti is unclear at present, as webb as that of the higher bevels of glutamate and aspartate in basilar membrane and spiral ganglion as compared to Reissner’s membrane, stria vascubaris and auditory nerve. The possibility that glutamate and/or aspartate may by synaptic transmitters in the cochlea at hair cell-to-auditory nerve fiber synapses seems worthy of further study.
not
that
not much
auditory were
while
mea-
auditory
regions.
in the
cat,3
aspartate
of precipitation
were
auditory
of the
been
to our
and
ganglion,
for the
has
concentration
from
cochbear
to
a specific
perilymph
by perilymph.
glycine the
nucbeus
glutamate The
in the
similar
membrane
freeze-drying
levels in spiral ganglion
those
in
On
it is noteworthy
gbycine than
involved
contribution
However,
(5)
synapses.
concentrations
amino
as
cord
about
high
sured
the
be
of glycine,
other
been
doses
spinal
in Reissner’s
a relatively
compared
from
of obivocochlear
intravenous may
found
where
transmitter
effects
glycine
of Corti,
vascularis
synaptic
matter,
at obivocochlear
the
in organ
the inhibition
transmission
those
gray
inhibitory
(6) at similar
suggests
synaptic
cord as an
glycine-rebated
further
and
spinal blocks
stimulation
does
the
cat
proposed
strychnine
bundle it
for been
in may
1. Berger method 2. Chan
SJ, for
AWK,
Carter glycine.
Burch
Downloaded from jhc.sagepub.com by guest on March 10, 2015
JA, Anal
HB,
CITED Lowry
OH:
Biochem
Abvey
TR,
An enzymatic 65:232, Lowry
1975 OH: A
470
LETTERS
approach glutamate.
to
TO
THE
EDITOR
renal Am J
and macuba sacculi of the guinea pig. I. Sampling procedures and analysis of’ pyridine nucleotides. Laryngoscope 77:292, 1967 Physiob 3. Crif’o 5, Crifb C: Free amino acid content of 15. Okada Y, Nitsch-Hassber C, Kim JS, Bak Ii, Hassler R: Role of y-aminobutyric acid (GABA) perilymph. Arch Otobaryngol 93:65, 1971 in the extrapyramidal motor system. 1. Regional 4. Curthoys NP, Lowry’ OH: Glutamate and glutadistribution of GABA in rabbit, rat, guinea pig mine distribution in the rat nephron in acidosis and baboon CNS. Exp Brain Res 13:514, 1971 and alkabosis. Am J Physiol 224:884, 1973 16. Otsuka M, Iversen LL, Hall ZW, Kravitz EA: 5. Curtis DR, Duggan AW, Johnston GAR: The Release of gamma-aminobutyric acid from inhibispecificity of strychnine as a glycine antagonist in tory’ nerves of lobster. Proc Natl Acad Sci USA the mammalian spinal cord. Exp Brain Res 56:110, 1966 12:547, 1971 17. Otsuka M, Obata K, Miyata Y, Tanaka Y: 6. Desmedt JE, Monaco P: Suppression par ba Measurement of’ -y-aminobutyric acid in isolated strychnine de b’effet inhibiteur centrifuge exerc#{233} quantitative transport. I.
histochemical
Aspartate 229:1034, 1975
par
and
obivocochb#{233}aire. Arch Int Phar1960 7. Fex J: Neural excitatory’ processes of’ the inner ear, Handbook of’ Sensory Physiology, Vol V/i: Auditory’ System. Edited by WD Keidel, WD Neff. Springer-Verlag, Berlin, 1974, p 585-646 8. Flock A. Lam DMK: Neurotransmitter synthesis in inner ear and lateral line sense organs. Nature 249: 142, 1974 macodyn
be faisceau 129:244,
9. Graham MH:
LT Jr.
Shank
Distribution
suspects
RP,
of
in cat
spinal
Werman
R, Aprison
some
synaptic
transmitter
cord.
J Neurochem
14:465,
1967 10. Klinke R, Galley N: Efferent innervation of vestibubar and auditory’ receptors. Physiob Rev 54:316, 1974 11. Kravitz EA, Molinof’f PB, Hall ZW: A comparison
of
the
enzymes
aminobutyric acid tory’ and inhibitory’ USA 54:778, 1965
12.
13.
14.
and
substrates
metabolism axons.
of in
Proc
‘y-aminobutrvic Brain Res Lam DMK: photoreceptors. 1972 Matschinsky tochemistry
acid system in rabbit 9:165, 1968 Biosynthesis of acetylcholine Proc Natb Acad Sci USA
21. Tachibana
22.
gamma-
B, Haber
B, Roberts
central
nervous
system.
J
M, Kuriyama
K: Gamma-aminobutyric
acid in the lower auditory pathway of the guinea pig. Brain Res 69:370, 1974 Thabmann R, Miyoshi T, Kusakari J, Ise I: Normal and abnormal energy metabolism of the inner ear. Otolaryngob Clin North Am 8:313, 1975
A. A.
GODFREY
JOYCE
retina.
SOSAMMA J. BERGER FRANz M. MATSCHINSKY Department of Pharmacology
in turtle 69:1987,
(D.A.G.,
OF THE PIG
CHOLINERGIC COCHLEA’
studies were supported by the National of Health through Research Grant NSO8000 and a National Institutes of Health Postdoctoral Fellowship to D. A. G. (#F02NS52,35402).
CARTER
J.A.C.,
S.J.B.,
F.M.M.)
Washington University School Central Institute for the Deaf St. Louis, Missouri 63110
FM, Thabmann R: Quantitative hisof the organ of’ Corti, stria vascubaris
ENZYMES
cat
E: The
Much evidence has been accumulated to suggest that acetylcholine acts as a chemical transmitter at cochlear synapses of the obivocochbear bundles (1, 5). However, one piece of evidence that is lacking is quantitative estimates of the cholinergic system in cochlear substructures. Using radiochemicab assays and methods of tissue preparation and sampling described elsewhere (2, 6), 1 These Institutes
of
DONALD
K, Sisken
OF
cells
Neurochem 18:287, 1971 18. Richrath W, Kraus H, Fromme HG: Lokalisation von 3H-’y-aminobuttersdure in der cochlea. Arch Otorhinolaryngologie 208:283, 1974 19. Ross CD, McDougal DB Jr: The distribution of choline acetyltransferase activity in vertebrate retina. J Neurochem, in press 20. Steinbach AB, Bennett MVL: Effects of divabent ions and drugs on synaptic transmission in phasic ebectroreceptors in a mormyrid fish. J Gen Physiob 58:580, 1971
lobster excitaNatb Acad Sci
Kuriyama
ACTIVITIES
nerve
activities
SYSTEM
of choline
linesterase,
the
basic
systems, were measured tissue dissected from cochlea was obtained Pieces of tissue were cochlear regions without examine the entirety of contents of each sample. were
split
cut
through
into
inner the
and
tunnel.
traveling at the floor organ of Corti samples
Downloaded from jhc.sagepub.com by guest on March 10, 2015
IN THE
acetyltransferase two
of Medicine (D.A.G.)
GUINEA
and
acetybcho-
of
chobinergic
enzymes
in microtubes for samples of freeze-dried cochbeas. Each from a separate guinea pig. dissected from the various attempting to systematically each region or check the exact The organ of Corti pieces outer The
hair basilar
cell
regions tunnel
by
a
fibers
of the tunnel were not in the but rather were likely to be in
JOURNAL
Copyright
OF
HISTOCHEMISTRY
© 1976 by The
AND
Histochemical
Vol.
CYTOCHEMISTRY
Society,
Inc.
Letters
LEVELS
OF
PUTATIVE
to the
2-.ig
samples
of
tissue
dissected
from
Editor
TRANSMITTER AMINO GUINEA PIG COCHLEA’
Although considerable effort has been directed toward establishing acetyichobine as a chemical transmitter at the obivocochlear synapses, investigation of the robe of other putative chemical transmitters in cochbear function is in a preliminary’ stage (7, 10). In order to provide some basic information relevant to the possible robe of amino acids as transmitters in the cochlea, we have measured levels of ‘y-aminobutyrate (GABA), glycine, glutamate and aspartate in 0.2- to a total
24, No, 2, pp. 468-472, 1976 Printed in LS.A.
ACIDS
IN
THE
dry weight for inner hair cell region. The data for the other cochhear regions had standard errors similar to those for organ of Corti. Our average level of 1.8 mmoles GABA/kg dry weight in organ of Corti compares with levels of 2.3-9.7 mmoles GABA/kg wet weight reported for various regions of the guinea pig brain (15) and bevels of 2-14 mmoles GABA/kg dry’ weight which we found for regions of a rat cochbear nucleus frozen immediately at death. Thalmann et al. (22) found even lower bevels of GABA in organ of Corti than we did, and Tachibana and Kuriyama (21) did not detect any. We did not find higher GABA bevels in spiral gangbion than in other cochlear regions, as Tachibana and Kuriyama did. The bow GABA bevels in organ of Corti and the finding of similar levels in cochbear regions which do not contain any part of the obivocochlear system (e.g., stria vascubaris and Reissner’s membrane) do not
of six
freeze-dried cochbeas, each obtained from a separate guinea pig. The sampling methods have been described previously ( 14). Samples were obtained from the various cochbear regions without attempting to sample systematically the entirety of each region or check the exact contents of each sample. The organ of Corti samples were split into inner and outer hair cell regions by a cut through the tunnel. The basilar tunnel fibers traveling at the floor of the tunnel were not in the organ of Corti samples but rather were likely to be in the basilar membrane samples. The assay procedures, by which all four of these amino acids were measured for each individual freeze-dried sample in oil wells, will be presented elsewhere’ but are based on published methods (1, 2, 4, 17). Low bevels of GABA were found in all cochlear regions examined, whereas levels of glycine were high for all regions (Fig. 1). Glutamate and aspartate levels were higher in the organ of Corti than in any other cochlear region. Additionally, there were gradients of aspartate bevels along the cochbear length of both inner and outer hair cehl regions. It should be mentioned that, since we were measuring all four amino acids in each sample and since the levels of all except GABA were quite high, the samples used did not provide amounts of GABA far above the bower limit of sensitivity of our GABA assay. The GABA bevels measured in individual organ of Corti samples had a considerable range: between -0.52 and +3.52 mmoles/kg dry weight for outer hair cell region and between --0.19 and +4.87 mmoles/kg
support
the
suggestion
of Richrath
et al.
(18)
that
the
efferent system of the organ of Corti contains a high concentration of GABA. This suggestion was based on the localization within the efferent system of tritiated GABA perfused through the cochlea. Further evidence against this possibility is our finding, to be reported in more detail elsewhere,3 that the part of the vestibubar nerve root where the olivocochbear bundles travel has bow GABA bevels weight). Evidently, cells may GABA without themselves Since the cochlear hair ble
proportion
of organ
for GABA are especially’ Flock and Lam (8) that transmitter
at
the
hair
(1-2 be
mmobes/kg dry abbe to take up
containing cells comprise of Corti
much GABA. a considera-
samples.
our
results
contrary’ to the suggestion GABA may be the chemical cell-to-auditory
nerve
of
syn-
apses. Their suggestion is based on in vitro synthesis of GABA by lateral line organs but does not consider the rates of synthesis in the context of those of other tissues. This is an important consideration, since neural tissues may contain small amounts of glutamic acid decarboxylase activity without either containing much GABA (11, 12) or releasing GABA as a transmitter (16). The approach used by Flock and Lam is similar to that (13) which bed to the suggestion. since indicated to be unlikely (19), that turtle photoreceptor cells may’ be chohinergic. The glycine levels for organ of Corti are similar to
‘These studies were supported by the American Cancer Society through Research Grant BC4Q, the National Institutes of Health through Research Grants NSO8000 and NS08862, and a National Institutes of Health Postdoctoral Fellowship to D. A. G. (F02NS52,35402). 2 Berger 5,1, CarterJA, Lowry OH: In preparation.
Godfrey Matschinsky
DA, Carter JA, Berger FM: In preparation.
468
Downloaded from jhc.sagepub.com by guest on March 10, 2015
SJ,
Lowry
OH,
LETFERS
TO THE
469
EDITOR
O’I-Amisobutyrats
80
luGlycini #{163} #{149} Glut.nats
80
6.taIs
70 60
150
50
40 30 20
20
----
10 7-
COCHLEAR HAIR
l0 I TURN CELLS
I FOR
RM OTHER
SV aM COCHLEAR
SG AN TISSUES
Ftc.. 1. Levels of amino acids for various regions of guinea pig cochlea. standard errors based on average values for individual cochbeas are presented regions of each cochbear turn. (For y-aminobutyrate, the standard errors Except for -y-aminobutyrate in the inner hair cell region of turn III, which point is based on samples from three to six cochbeas. Samples were obtained regions of all four cochlear turns for three cochleas in the case of aspartate,
For the organ of Corti, means and for inner (I) and outer (0) hair cell fall within the size of the circles.) is based on two cochbeas, each data from both inner and outer hair cell two for the other amino acids.
For the other cochbear regions, data from the various turns are grouped. Means are presented, based on samples from two to five cochbeas. RM, Reissner’s membrane: SV, stria vascularis; BM, basilar membrane; SG, spiral ganglion; AN, auditory nerve central to spiral ganglion. For comparison with the cochlear results, bevels of the four amino acids measured in an extract of a piece of frontal cortex removed from an anesthetized cat and immediately frozen (values converted to an equivalent dry weight basis by multiplying by five) were 3.8 mmoles GABA, 3.5 mmobes glycine, 47 mmoles glutamate and 12 mmoles aspartate/kg equivalent dry weight. those
reported
glycine
has
(9).
That
other
that
hand,
stria
high
role
raise here
to contain
glycine
as
in
bevels
of glycine
It is of interest reported
some
doubts
in the
cochlea.
that
horse
to
the
acids
(3).
amino
acid
bevels
resulting
fluids
during
determined.
cochlear
The
regions
not bathed
ble
that
central which
the to we
cochlear
organ
found and
higher of
other
Corti
bevels
spiral
most
of
has
nerve
nerve
were
bevels
of
glutamate
than
in
other
as it enters
the
less
region,
times
levels
cochbear
We
thank
Dr.
dissecting
the
McDougab,
Jr.
script, script
those
aspartate regions
J.
J.
Krzanowski,
freeze-dried for
Jr.
for
cochbeas,
critical
Mrs. Barbara and Anne Fuller
evaluation
Pordy Dillon
help
Dr. of
for typing for drawing
the
with D.
B.
manu-
the manuthe figure.
the
LITERATURE
of GABA,
similar. and
ACKNOWLEDc.MENTS
the
nerve,
It is remarkafour
suggest the involvement of these amino acids in cochbear synaptic transmission. Both were reported to “act bike transmitters” at the synapses of medium electroreceptors of the acousticolaterahis system in a mormyrid fish (20). However, our data do not permit conclusions about distribution of glutamate or aspartate among the various types of cells contained in the organ of Corti samples. The significance of the aspartate gradient in organ of Corti is unclear at present, as webb as that of the higher bevels of glutamate and aspartate in basilar membrane and spiral ganglion as compared to Reissner’s membrane, stria vascubaris and auditory nerve. The possibility that glutamate and/or aspartate may by synaptic transmitters in the cochlea at hair cell-to-auditory nerve fiber synapses seems worthy of further study.
not
that
not much
auditory were
while
mea-
auditory
regions.
in the
cat,3
aspartate
of precipitation
were
auditory
of the
been
to our
and
ganglion,
for the
has
concentration
from
cochbear
to
a specific
perilymph
by perilymph.
glycine the
nucbeus
glutamate The
in the
similar
membrane
freeze-drying
levels in spiral ganglion
those
in
On
it is noteworthy
gbycine than
involved
contribution
However,
(5)
synapses.
concentrations
amino
as
cord
about
high
sured
the
be
of glycine,
other
been
doses
spinal
in Reissner’s
a relatively
compared
from
of obivocochlear
intravenous may
found
where
transmitter
effects
glycine
of Corti,
vascularis
synaptic
matter,
at obivocochlear
the
in organ
the inhibition
transmission
those
gray
inhibitory
(6) at similar
suggests
synaptic
cord as an
glycine-rebated
further
and
spinal blocks
stimulation
does
the
cat
proposed
strychnine
bundle it
for been
in may
1. Berger method 2. Chan
SJ, for
AWK,
Carter glycine.
Burch
Downloaded from jhc.sagepub.com by guest on March 10, 2015
JA, Anal
HB,
CITED Lowry
OH:
Biochem
Abvey
TR,
An enzymatic 65:232, Lowry
1975 OH: A
470
LETTERS
approach glutamate.
to
TO
THE
EDITOR
renal Am J
and macuba sacculi of the guinea pig. I. Sampling procedures and analysis of’ pyridine nucleotides. Laryngoscope 77:292, 1967 Physiob 3. Crif’o 5, Crifb C: Free amino acid content of 15. Okada Y, Nitsch-Hassber C, Kim JS, Bak Ii, Hassler R: Role of y-aminobutyric acid (GABA) perilymph. Arch Otobaryngol 93:65, 1971 in the extrapyramidal motor system. 1. Regional 4. Curthoys NP, Lowry’ OH: Glutamate and glutadistribution of GABA in rabbit, rat, guinea pig mine distribution in the rat nephron in acidosis and baboon CNS. Exp Brain Res 13:514, 1971 and alkabosis. Am J Physiol 224:884, 1973 16. Otsuka M, Iversen LL, Hall ZW, Kravitz EA: 5. Curtis DR, Duggan AW, Johnston GAR: The Release of gamma-aminobutyric acid from inhibispecificity of strychnine as a glycine antagonist in tory’ nerves of lobster. Proc Natl Acad Sci USA the mammalian spinal cord. Exp Brain Res 56:110, 1966 12:547, 1971 17. Otsuka M, Obata K, Miyata Y, Tanaka Y: 6. Desmedt JE, Monaco P: Suppression par ba Measurement of’ -y-aminobutyric acid in isolated strychnine de b’effet inhibiteur centrifuge exerc#{233} quantitative transport. I.
histochemical
Aspartate 229:1034, 1975
par
and
obivocochb#{233}aire. Arch Int Phar1960 7. Fex J: Neural excitatory’ processes of’ the inner ear, Handbook of’ Sensory Physiology, Vol V/i: Auditory’ System. Edited by WD Keidel, WD Neff. Springer-Verlag, Berlin, 1974, p 585-646 8. Flock A. Lam DMK: Neurotransmitter synthesis in inner ear and lateral line sense organs. Nature 249: 142, 1974 macodyn
be faisceau 129:244,
9. Graham MH:
LT Jr.
Shank
Distribution
suspects
RP,
of
in cat
spinal
Werman
R, Aprison
some
synaptic
transmitter
cord.
J Neurochem
14:465,
1967 10. Klinke R, Galley N: Efferent innervation of vestibubar and auditory’ receptors. Physiob Rev 54:316, 1974 11. Kravitz EA, Molinof’f PB, Hall ZW: A comparison
of
the
enzymes
aminobutyric acid tory’ and inhibitory’ USA 54:778, 1965
12.
13.
14.
and
substrates
metabolism axons.
of in
Proc
‘y-aminobutrvic Brain Res Lam DMK: photoreceptors. 1972 Matschinsky tochemistry
acid system in rabbit 9:165, 1968 Biosynthesis of acetylcholine Proc Natb Acad Sci USA
21. Tachibana
22.
gamma-
B, Haber
B, Roberts
central
nervous
system.
J
M, Kuriyama
K: Gamma-aminobutyric
acid in the lower auditory pathway of the guinea pig. Brain Res 69:370, 1974 Thabmann R, Miyoshi T, Kusakari J, Ise I: Normal and abnormal energy metabolism of the inner ear. Otolaryngob Clin North Am 8:313, 1975
A. A.
GODFREY
JOYCE
retina.
SOSAMMA J. BERGER FRANz M. MATSCHINSKY Department of Pharmacology
in turtle 69:1987,
(D.A.G.,
OF THE PIG
CHOLINERGIC COCHLEA’
studies were supported by the National of Health through Research Grant NSO8000 and a National Institutes of Health Postdoctoral Fellowship to D. A. G. (#F02NS52,35402).
CARTER
J.A.C.,
S.J.B.,
F.M.M.)
Washington University School Central Institute for the Deaf St. Louis, Missouri 63110
FM, Thabmann R: Quantitative hisof the organ of’ Corti, stria vascubaris
ENZYMES
cat
E: The
Much evidence has been accumulated to suggest that acetylcholine acts as a chemical transmitter at cochlear synapses of the obivocochbear bundles (1, 5). However, one piece of evidence that is lacking is quantitative estimates of the cholinergic system in cochlear substructures. Using radiochemicab assays and methods of tissue preparation and sampling described elsewhere (2, 6), 1 These Institutes
of
DONALD
K, Sisken
OF
cells
Neurochem 18:287, 1971 18. Richrath W, Kraus H, Fromme HG: Lokalisation von 3H-’y-aminobuttersdure in der cochlea. Arch Otorhinolaryngologie 208:283, 1974 19. Ross CD, McDougal DB Jr: The distribution of choline acetyltransferase activity in vertebrate retina. J Neurochem, in press 20. Steinbach AB, Bennett MVL: Effects of divabent ions and drugs on synaptic transmission in phasic ebectroreceptors in a mormyrid fish. J Gen Physiob 58:580, 1971
lobster excitaNatb Acad Sci
Kuriyama
ACTIVITIES
nerve
activities
SYSTEM
of choline
linesterase,
the
basic
systems, were measured tissue dissected from cochlea was obtained Pieces of tissue were cochlear regions without examine the entirety of contents of each sample. were
split
cut
through
into
inner the
and
tunnel.
traveling at the floor organ of Corti samples
Downloaded from jhc.sagepub.com by guest on March 10, 2015
IN THE
acetyltransferase two
of Medicine (D.A.G.)
GUINEA
and
acetybcho-
of
chobinergic
enzymes
in microtubes for samples of freeze-dried cochbeas. Each from a separate guinea pig. dissected from the various attempting to systematically each region or check the exact The organ of Corti pieces outer The
hair basilar
cell
regions tunnel
by
a
fibers
of the tunnel were not in the but rather were likely to be in
