Physiology & Behavior, Vol. 23, pp. 39--41. Pergamon Press and Brain Research Publ., 1979. Printed in the U.S.A.
Motion Sickness-Induced Food Aversions in the Squirrel Monkey I M. A A R O N ROY z A N D K E N N E T H R. B R I Z Z E E
Neurobiology Department, Delta Regional Primate Research Center, Covington, LA 70433 Received 22 June 1978 ROY, M. A. AND K. R. BRIZZEE. Motion sickness-induced food aversions in the Squirrel monkey. PHYSIOL. BEHAV. 23(1) 39--41, 1979.--Conditioned aversions to colored, flavored water were established in Squirrel monkeys (Saimiri sciureus) by following consumption with 90 min of simultaneous rotational and vertical stimulation. The experimental group (N = 13) drank significantly less of the green, almond-flavored test solution than did the control group (N = 14) during three post-treatment preference testing days. Individual differences were noted in that two experimental monkeys readily drank the test solution after rotational stimulation. Only two of the experimental monkeys showed emesis during rotation, yet 10 monkeys in this group developed an aversion. These results suggest that (1) motion sickness can be readily induced in Squirrel monkeys with simultaneous rotational and vertical stimulation and (2) that conditioned food aversions are achieved in the absence of emesis in this species.
Conditioned food aversions
Motionsickness
Squirrelmonkeys
ACQUIRED aversions to particular flavored or colored foods have been investigated by learning theorists to increase their understanding of conditioning principles [8,9]. Conditioned taste aversions are usually studied. Most often, the aversion is apparently achieved by inducing gastrointestinal malaise with an emetic agent such as LiCI [6], apomorphine [21], x-irradiation [8,10], or rotational stimulation [9,11]. However, taste aversions have been reported in monkeys who do not exhibit apparent nausea [7]. Conditioned food aversions have been used to investigate issues other than learning paradigms. There are reports this paradigm is advantageous when studying pituitary and adrenal peptide activity [21] and the neural substrates of nausea [20]. The assessment of drug-nausea relationships with conditioned taste aversions may eventually prove to be useful [15, 16, 17]. Rotational stimulation has been successful in inducing motion sickness in rats as shown by the development of taste aversionsin rats [1]. Squirrel monkeys do exhibit emesis in response to motion [4,13] and drugs [4], but work in our laboratory concerning the area postrema and its role in motion sickness found that only about 40% of naive Squirrel monkeys do vomit to simultaneous rotational and vertical movement [4]. We felt that the development of a food aversion in non-vomiting monkeys could signal nausea without the presence of the accepted behavioral criteria for nausea. METHOD
Animals Thirty two Squirrel monkeys ($aimiri sciureus) of mixed
sex and sub-species, but all feral-reared adults, were studied. Each experimental and some control animals had previously been tested for emesis with the motion sickness apparatus described below, but none had shown any emesis. The monkeys' only previous contact with a flavored liquid was a weekly supplement of Tang® (General Foods Corporation, White Plains, NY) which terminated two wks before the onset of this experiment.
Apparatus The rotary motion device consisted of a ventilated, transparent, plastic (18x 10x30 cm) or wire (15x 15x30 cm) rotation chamber mounted on a motor-driven platform which had two simultaneous modes of movement: counterclockwise circular rotation at 65 RPM and vertical excursion of 3 in. at the rate of 30 per min. The platform was horizontal to the floor.
Procedure All monkeys were housed in individual cages with ad lib Purina Monkey Chow 25® (Ralston Purina Co., St. Louis, MO) for 7 days, On Days 1-3, each animal's daily water intake was recorded from a single water bottle fitted with a standard ball-filled lick tube (Atco Mfg., Napa, CA). The monkeys were water deprived at 1 p.m. on Day 3 to maximize consumption of the test solution to be provided on the morning of Day 4. A green-tinted, 5% almond-flavored solution (McCormick® almond extract, McCormick Co., Baltimore, MD) was given to each monkey between 8-9:30 a. m.
1This research was supported by NASA Ames NSG 2139 and NIH RR00164-16. ZPresent address at which reprints may be requested: M. Aaron Roy, Psychology Department, Northern Michigan University, Marquette, MI 49855.
Copyright © 1979 Brain Research Publications Inc.--0031-9384/79/070039-03502.00/0
40
ROY A N D B R I Z Z E ~ "FABLE 1 COMSUMPT1ON RATES OF THE FLAVORED SOLUTION
Animal
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 CII C12 C13 C14
Control Pre-Spin Percentage of Flavored Flavor Water Consumed Consumption Day 5 Day 6 Day 7 ml % % %
30 27 49 38 43 20 20 10 18 22 15 35 47 29 MEAN = 28.8
93 49 77 13 97 64 8 7 13 14 42 60 50 13 42.9
78 II 89 10 54 14 19 14 17 57 14 47 79 31 38.1
38 17 95 19 19 61 27 0 10 34 18 73 52 97 40.0
Emetic Response
Animal
El E2 E3 E4 E5 E6 E7 E8 E9 El0 Ell El2 El3
on Day 4. Immediately thereafter, the m o n k e y was placed in a 3 1 x 3 1 × 4 1 c m m e t a l a n d Plexiglas t r a n s p o r t cage a n d rem o v e d to the r o o m c o n t a i n i n g the r o t a r y - m o t i o n device. This c h a n g e in l o c a t i o n t o o k place w i t h i n 10 min. E x p e r i m e n t a l a n i m a l s were t h e n p l a c e d in the r o t a t i o n c h a m b e r a n d e x p o s e d to 90 m i n o f r o t a t i o n a l a n d vertical m o t i o n . E v e r y 20 m i n t h e m o v e m e n t w a s s t o p p e d for 30 sec to r e c o r d n y s t a g m u s a n d verify a n y emesis. While e a c h e x p e r i m e n t a l a n i m a l was b e i n g r o t a t e d , a c o n t r o l m o n k e y rem a i n e d in its t r a n s p o r t cage a n d w a s p o s i t i o n e d next to t h e r o t a t i o n d e v i c e b u t facing a w a y f r o m it. T h e m o n k e y s w e r e t h e n r e t u r n e d to t h e i r h o m e c a g e s w h e r e , 15 min a f t e r t h e i r r e t u r n , t w o identical b o t t l e s fitted with identical lick t u b e s w e r e p r o v i d e d . O n e b o t t l e c o n t a i n e d tap w a t e r , the o t h e r c o n t a i n e d the t e s t s u b s t a n c e . I n t a k e of e a c h liquid w a s t h e n r e c o r d e d d u r i n g e a c h of t h r e e s u c c e s s i v e 24 h o u r time periods. A n i m a l a s s i g n m e n t to c o n t r o l o r e x p e r i m e n t a l c o n d i t i o n was b a s e d o n t h e a m o u n t o f the test solution which was c o n s u m e d o n t h e m o r n i n g o f Day 4.
+ + -
Experimental Pre-Spin Percentage of Flavored Flavor Water Consumed Consumption Day 5 Day 6 Day 7 ml 9~ ~ ';~ 15 15 28 30 19 25 33 24 37 10 57 27 40
Mean = 27.7
15 8 0 85 13 3 2 11 9 11 7 3 47
14 6 0 3 27 0 1 34 6 2 21 9 38
21 0 0 85 12 3 59 7 6 6 6 51
16.5
12.4
19.7
o
O-Col~rot •-EXl~rimenlal
_ 4o It~f) 3o
RESULTS F i v e m o n k e y s were d i s c a r d e d a f t e r d r i n k i n g less t h a n 10 ml o f the test s u b s t a n c e o n the m o r n i n g o f Day 4. F o r the r e m a i n i n g a n i m a l s , t h e a m o u n t of the t e s t s o l u t i o n w h i c h w a s c o n s u m e d p r i o r to s h a m or a c t u a l r o t a t i o n in t h e m o t i o n d e v i c e , t h e p r e s e n c e or a b s e n c e o f e m e s i s d u r i n g r o t a t i o n , a n d t h e p e r c e n t a g e o f the t e s t s u b s t a n c e w h i c h was cons u m e d o n t h e t h r e e p r e f e r e n c e testing d a y s are p r e s e n t e d in T a b l e 1. T h e r e was n o difference b e t w e e n control ( 5(=28.8 ml) or experimental ( 5(=27.7 ml) groups in their average consumption o f t h e test s o l u t i o n p r i o r to e x p o s u r e to v e r t i c a l a n d r o t a t i o n a l m o t i o n . A s s e e n in Fig. 1, t h e e x p e r i m e n t a l g r o u p c o n s u m e d less o f t h e test s u b s t a n c e o n all 3 p r e f e r e n c e test-
I 5 PREFERENCE
I 6 TESTING
I 7 DAYS
FIG. 1. Percentage of flavored solution consumed during preference testing days.
R O T A T I O N - I N D U C E D FOOD AVERSIONS IN MONKEYS ing days than did the control group. These group differences were significant, F(1,25)=9.06, p
Motion Sickness-Induced Food Aversions in the Squirrel Monkey I M. A A R O N ROY z A N D K E N N E T H R. B R I Z Z E E
Neurobiology Department, Delta Regional Primate Research Center, Covington, LA 70433 Received 22 June 1978 ROY, M. A. AND K. R. BRIZZEE. Motion sickness-induced food aversions in the Squirrel monkey. PHYSIOL. BEHAV. 23(1) 39--41, 1979.--Conditioned aversions to colored, flavored water were established in Squirrel monkeys (Saimiri sciureus) by following consumption with 90 min of simultaneous rotational and vertical stimulation. The experimental group (N = 13) drank significantly less of the green, almond-flavored test solution than did the control group (N = 14) during three post-treatment preference testing days. Individual differences were noted in that two experimental monkeys readily drank the test solution after rotational stimulation. Only two of the experimental monkeys showed emesis during rotation, yet 10 monkeys in this group developed an aversion. These results suggest that (1) motion sickness can be readily induced in Squirrel monkeys with simultaneous rotational and vertical stimulation and (2) that conditioned food aversions are achieved in the absence of emesis in this species.
Conditioned food aversions
Motionsickness
Squirrelmonkeys
ACQUIRED aversions to particular flavored or colored foods have been investigated by learning theorists to increase their understanding of conditioning principles [8,9]. Conditioned taste aversions are usually studied. Most often, the aversion is apparently achieved by inducing gastrointestinal malaise with an emetic agent such as LiCI [6], apomorphine [21], x-irradiation [8,10], or rotational stimulation [9,11]. However, taste aversions have been reported in monkeys who do not exhibit apparent nausea [7]. Conditioned food aversions have been used to investigate issues other than learning paradigms. There are reports this paradigm is advantageous when studying pituitary and adrenal peptide activity [21] and the neural substrates of nausea [20]. The assessment of drug-nausea relationships with conditioned taste aversions may eventually prove to be useful [15, 16, 17]. Rotational stimulation has been successful in inducing motion sickness in rats as shown by the development of taste aversionsin rats [1]. Squirrel monkeys do exhibit emesis in response to motion [4,13] and drugs [4], but work in our laboratory concerning the area postrema and its role in motion sickness found that only about 40% of naive Squirrel monkeys do vomit to simultaneous rotational and vertical movement [4]. We felt that the development of a food aversion in non-vomiting monkeys could signal nausea without the presence of the accepted behavioral criteria for nausea. METHOD
Animals Thirty two Squirrel monkeys ($aimiri sciureus) of mixed
sex and sub-species, but all feral-reared adults, were studied. Each experimental and some control animals had previously been tested for emesis with the motion sickness apparatus described below, but none had shown any emesis. The monkeys' only previous contact with a flavored liquid was a weekly supplement of Tang® (General Foods Corporation, White Plains, NY) which terminated two wks before the onset of this experiment.
Apparatus The rotary motion device consisted of a ventilated, transparent, plastic (18x 10x30 cm) or wire (15x 15x30 cm) rotation chamber mounted on a motor-driven platform which had two simultaneous modes of movement: counterclockwise circular rotation at 65 RPM and vertical excursion of 3 in. at the rate of 30 per min. The platform was horizontal to the floor.
Procedure All monkeys were housed in individual cages with ad lib Purina Monkey Chow 25® (Ralston Purina Co., St. Louis, MO) for 7 days, On Days 1-3, each animal's daily water intake was recorded from a single water bottle fitted with a standard ball-filled lick tube (Atco Mfg., Napa, CA). The monkeys were water deprived at 1 p.m. on Day 3 to maximize consumption of the test solution to be provided on the morning of Day 4. A green-tinted, 5% almond-flavored solution (McCormick® almond extract, McCormick Co., Baltimore, MD) was given to each monkey between 8-9:30 a. m.
1This research was supported by NASA Ames NSG 2139 and NIH RR00164-16. ZPresent address at which reprints may be requested: M. Aaron Roy, Psychology Department, Northern Michigan University, Marquette, MI 49855.
Copyright © 1979 Brain Research Publications Inc.--0031-9384/79/070039-03502.00/0
40
ROY A N D B R I Z Z E ~ "FABLE 1 COMSUMPT1ON RATES OF THE FLAVORED SOLUTION
Animal
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 CII C12 C13 C14
Control Pre-Spin Percentage of Flavored Flavor Water Consumed Consumption Day 5 Day 6 Day 7 ml % % %
30 27 49 38 43 20 20 10 18 22 15 35 47 29 MEAN = 28.8
93 49 77 13 97 64 8 7 13 14 42 60 50 13 42.9
78 II 89 10 54 14 19 14 17 57 14 47 79 31 38.1
38 17 95 19 19 61 27 0 10 34 18 73 52 97 40.0
Emetic Response
Animal
El E2 E3 E4 E5 E6 E7 E8 E9 El0 Ell El2 El3
on Day 4. Immediately thereafter, the m o n k e y was placed in a 3 1 x 3 1 × 4 1 c m m e t a l a n d Plexiglas t r a n s p o r t cage a n d rem o v e d to the r o o m c o n t a i n i n g the r o t a r y - m o t i o n device. This c h a n g e in l o c a t i o n t o o k place w i t h i n 10 min. E x p e r i m e n t a l a n i m a l s were t h e n p l a c e d in the r o t a t i o n c h a m b e r a n d e x p o s e d to 90 m i n o f r o t a t i o n a l a n d vertical m o t i o n . E v e r y 20 m i n t h e m o v e m e n t w a s s t o p p e d for 30 sec to r e c o r d n y s t a g m u s a n d verify a n y emesis. While e a c h e x p e r i m e n t a l a n i m a l was b e i n g r o t a t e d , a c o n t r o l m o n k e y rem a i n e d in its t r a n s p o r t cage a n d w a s p o s i t i o n e d next to t h e r o t a t i o n d e v i c e b u t facing a w a y f r o m it. T h e m o n k e y s w e r e t h e n r e t u r n e d to t h e i r h o m e c a g e s w h e r e , 15 min a f t e r t h e i r r e t u r n , t w o identical b o t t l e s fitted with identical lick t u b e s w e r e p r o v i d e d . O n e b o t t l e c o n t a i n e d tap w a t e r , the o t h e r c o n t a i n e d the t e s t s u b s t a n c e . I n t a k e of e a c h liquid w a s t h e n r e c o r d e d d u r i n g e a c h of t h r e e s u c c e s s i v e 24 h o u r time periods. A n i m a l a s s i g n m e n t to c o n t r o l o r e x p e r i m e n t a l c o n d i t i o n was b a s e d o n t h e a m o u n t o f the test solution which was c o n s u m e d o n t h e m o r n i n g o f Day 4.
+ + -
Experimental Pre-Spin Percentage of Flavored Flavor Water Consumed Consumption Day 5 Day 6 Day 7 ml 9~ ~ ';~ 15 15 28 30 19 25 33 24 37 10 57 27 40
Mean = 27.7
15 8 0 85 13 3 2 11 9 11 7 3 47
14 6 0 3 27 0 1 34 6 2 21 9 38
21 0 0 85 12 3 59 7 6 6 6 51
16.5
12.4
19.7
o
O-Col~rot •-EXl~rimenlal
_ 4o It~f) 3o
RESULTS F i v e m o n k e y s were d i s c a r d e d a f t e r d r i n k i n g less t h a n 10 ml o f the test s u b s t a n c e o n the m o r n i n g o f Day 4. F o r the r e m a i n i n g a n i m a l s , t h e a m o u n t of the t e s t s o l u t i o n w h i c h w a s c o n s u m e d p r i o r to s h a m or a c t u a l r o t a t i o n in t h e m o t i o n d e v i c e , t h e p r e s e n c e or a b s e n c e o f e m e s i s d u r i n g r o t a t i o n , a n d t h e p e r c e n t a g e o f the t e s t s u b s t a n c e w h i c h was cons u m e d o n t h e t h r e e p r e f e r e n c e testing d a y s are p r e s e n t e d in T a b l e 1. T h e r e was n o difference b e t w e e n control ( 5(=28.8 ml) or experimental ( 5(=27.7 ml) groups in their average consumption o f t h e test s o l u t i o n p r i o r to e x p o s u r e to v e r t i c a l a n d r o t a t i o n a l m o t i o n . A s s e e n in Fig. 1, t h e e x p e r i m e n t a l g r o u p c o n s u m e d less o f t h e test s u b s t a n c e o n all 3 p r e f e r e n c e test-
I 5 PREFERENCE
I 6 TESTING
I 7 DAYS
FIG. 1. Percentage of flavored solution consumed during preference testing days.
R O T A T I O N - I N D U C E D FOOD AVERSIONS IN MONKEYS ing days than did the control group. These group differences were significant, F(1,25)=9.06, p
