Physiology & Behavior, Vol. 19, pp.

573--575. Pergamon Press and Brain Research Publ., 1977. Printed in the U.S.A.

BRIEF COMMUNICATION Schedule-Induced Polydipsia in the Guinea Pig I JOSEPH H. PORTER, NAZAN N. SOZER AND THOMAS P. MOESCHL

Department o f Psychology, Virginia Commonwealth University, Richmond, VA 23284 (Received 17 May 1977) PORTER, J. H., N. N. SOZER AND T. P. MOESCHL. Schedule-induced polydipsia in theguinea pig. PHYSIOL. BEHAV. 19(4) 573-575, 1977. - Two of three food-deprived guinea pigs displayed schedule4nduced polydipsia when 45 mg food pellets were delivered according to a fixed-time 1-min food schedule. Both animals displayed the typical postpellet pattern of adjunctive drinking. These data extend the generality of schedule-induced polydipsia to a new species. Schedule-induced polydipsia

Schedule-induced drinking

Adjunctive behavior

SCHEDULE-INDUCED polydipsia in rats was first reported by John Falk in 1961 [2]. Since then, numerous studies have been conducted in an attempt to explain this phenomenon. One finding has been the apparent generality of schedule-induced polydipsia to different species of animals, including mice [8,9], rhesus monkeys [1, 10, 11, 12], several different strains of rats [3], pigeons [7,13], and humans [6]. Recently, Wilson and Spencer [14] reported that hamsters did not display excessive drinking when tested in the standard schedule-induced polydipsia paradigm. This demonstration of a species limitation of schedule-induced polydipsia prompted the present investigation. Schedule-induced polydipsia was studied in guinea pigs in order to provide further evidence for the species generality or limitations of this phenomenon.

was not on during test sessions. White noise was present during each session, the standard electromechanical programming and recording equipment were located in an adjacent room.

Procedure Fifty-rain test sessions were conducted Monday through Friday, and the guinea pigs were maintained at their reduced body weights over the weekend. For the first 12 sessions, 50 food pellets were placed in the food magazine and the guinea pigs were placed in the test chamber for 50-min. All 50 pellets were consumed during the 50-min sessions. This allowed baseline measures of water consumption in response to 50 food pellets to be determined. From Session 13 to Session33, 50 food pellets were delivered according to a fixed time (FT) 1-min reinforcement schedule, in which a pellet was delivered every minute independently of the guinea pig's behavior. Baseline measures were taken again for 11 sessions for G P - 5 and G P - 6 and 8 sessions for G P - 7 by test chamber for 50-min. Total water consumption was determined by weighing the water bottle before and after each session to the nearest 0.5 g. Water spillage due to the handling of the bottles was subtracted before complating total session intakes. For convenience, water intake is reported in milliliters (1 g = 1 ml). RESULTS

METHOD

Animals The animals were three naive male albino guinea pigs with a mean weight of 427 g at the beginning of the experiment. They were individually caged in an animal colony room (7 a.m. to 6 p.m. light/dark cycle), and maintained at 85% of their free-feeding body weights by adjusting their daily ration of Purina Guinea Pig chow. The diet was supplemented with liquid vitamin C which was mixed in the home cage drinking water.

Two of the three guinea pigs displayed schedule-induced polydipsia. Table 1 shows the mean water intake and water tube contacts for the last three sessions of each condition. For G P - 6 and G P - 7 , both water intake and tube contacts increased substantially from baseline to the FT 1-min condition and decreased again upon return to baseline. G P - 5 also showed a large increase in the number of tube contacts, but did not show any increase in water consumption. Examination of cumulative records revealed that

Apparatus Test sessions were conducted in two Scientific Prototype operant-conditioning chambers (Model A - 1 0 0 ) w h i c h were housed in sound-attenuated cubicles. A water bottle was mounted behind the intelligence panel on the right-hand side with the m e t a l drinking spout protruding approximately 15 mm into the test chamber. Reinforcers were 45 mg standard formula Noyes pellets. The houselight

~The authors would like to thank Judi Platko for assisting in data collection. Reprint requests should be sent to Joseph H. Porter, Department of Psychology, Virginia Commonwealth University, Richmond, VA 23284. 573

574

PORTER,

TABLE

SOZER

ANI) MOt!S('[tl

1

MEAN WATER INTAKE (ML) AND TUBE CONTACTS FOR THE L A S T THREE SESSIONS OF EACH CONDITION Animal Baseline

W a t e r Intake FT l - - m i n

Baseline

GP--5

0.3

0.2

0.0

4.3

127.0

4.0

GP--6

0.5

5.2

2.1

14.3

221.3

113.0

GP--7

0.0

19.5

1.7

1.7

353.3

28.7

TABLE

Baseline

Tube Contacls FT l - - r a i n

Baseline

2

MEAN ML PER PELLET AND PERCENT INTERVALS IN WHICH DRINKING OCCURRED FOR THE LAST THREE SESSIONS OF EACH CONDITION

Animal Baseline

ml/pellet FT 1--min

Baseline

Baseline

FT

I-MIN

BASELINE

Baseline

GP---5

0.0

0.0

0.0

7.3

30.7

8.0

GP---6

0.0

0.1

0.0

17.7

65.3

19.3

GP--7

0.0

0.4

0.0

10.0

53.3

18.7

GP-6 BASELINE

% intervals FT 1 - - m i n

GP-7 BASELINE

FT

I-MIN

BASELINE

FIG. 1. Sample cumulative records for G P - 6 and G P - 7 from the last three sessions of the baseline and FT 1-min conditions. Contacts on the drinking tube advanced the response pen, and pellet deliveries are indicated by the downward deflections.

POLYDIPSIA IN THE G U I N E A PIG

575

the pattern of tube contacts for G P - 5 resembled a fixed-interval scallop in that the number of contacts increased throughout the interval and reached a peak just prior to pellet delivery. In Table 2, water intake for the last three sessions of each condition is expressed in milliliters per pellet. Once again, G P - 6 and G P - 7 showed an increase in water consumption during the FT 1-min condition as compared to baseline. Table 2 also presents the percent of intervals in which drinking (or tube contacts) actually occurred for the last three sessions of each condition. Each animal displayed an increase during the FT 1-min condition with G P - 6 and G P - 7 drinking during more intervals than G P - 5 . Actually, for G P - 5 these data represent the percent of intervals in which tube contact was made, since almost no water was consumed. Figure 1 presents sample cumulative records for G P - 6 and G P - 7 from the last three sessions of the two baseline conditions and the FT 1-min conditions. Examination of the pattern of drinking during the FT 1-min food schedule shows that G P - 6 and G P - 7 usually drank immediately following pellet delivery (in those intervals in which drinking occurred). This postpellet or prandial pattern of

drinking is one of the characteristics of schedule-induced polydipsia which has been shown in other species [3,4]. DISCUSSION The present study demonstrated that schedule-induced polydipsia does occur in guinea pigs. Two of the three guinea pigs showed an increase in water consumption when food pellets were delivered according to an FT 1-min schedule. The session intake of 19.55 ml of water for G P - 7 is quite similar to the amounts of water consumed by rats during 50-min sessions in this laboratory. Freed, Zec and Mendelson [ 5 ] have reported that guinea pigs will display schedule-induced licking of a cold metal tube, but they failed to find any evidence of scheduleinduced polydipsia in guinea pigs. While it is unclear why Freed etal. [5] did not find schedule-induced polydipsia, the results of the present study clearly demonstrate that schedule-induced polydipsia can be shown in guinea pigs. The present data extend the generality of schedule-induced polydipsia to a new species and indicate the importance of further studies on the species generality or limitation of schedule-induced polydipsia and other schedule-induced behaviors.

REFERENCES 1. Allen, J. D. and D. R. Kenshalo, Jr. Sche~lule-induced drinking as a function of interreinforcement interval in the rhesus monkey. J. exp. Analysis Behav. 26: 257-267, 1976. 2. Falk, J. L. Production of polydipsia in normal rats by an intermittent food schedule. Science 33: 195-196, 1961. 3. Falk, J. L. Conditions producing psychogenic polydipsia in animals. Ann. N. Y. Acad. ScL 157: 569-589, 1969. 4. Falk, J. L. The nature and determinants of adjunctive behavior. Physiol. Behav. 6: 577-588, 1971. 5. Freed, W. J., R. F. Zec and J. Mendelson. Schedule-induced polydipsia: The role of oroligual factors and a new hypothesis. In: Drinking Behavior: Oral Stimulation, Reinforcement and Preference, edited by J. A. W. M. Weijnen and J. Mendelson. New York: Plenum, in press. 6. Kachanoff, R., R. Leveille, J. P. McLelland and M. J. Wayner. Schedule-induced behavior in humans. Physiol. Behav. 11: 395-398, 1973. 7. Magyar, R. L., R. Allen, A. Sicignano and E. F. Malagodi. Schedule-induced polydipsia in the pigeon. Paper presented at the meeting of the Southeastern Psychological Association, Hollywood, Florida, 1977.

8. Ogata, H., F. Ogata, J. H. Mendelson and N. K. Mello. A comparison of techniques to induce alcohol dependence and tolerance in the mouse. J. Pharmac. exp. Ther. 180: 216-230, 1972. 9. Palfai, T., C. L. Kutscher and J. P. Symons. Schedule-induced polydipsia in the mouse. Physiol. Behav. 6:461-462, 1971. 10. Porter, J. H. and D. R. Kenshalo, Jr. Schedule-induced drinking following omission of reinforcement in the rhesus monkey. Physiol. Behav. 12: 1075-1077, 1974. 11. Salzberg, C. L., W. W. Henton and J. J. Jordan. Concurrent water drinking on FT and CRF food-reinforcement schedules in the rhesus monkey. Psychol. Rep. 22: 1065-1970, 1968. 12. Schuster, C. R. and J. H. Woods. Schedule-induced polydipsia in the rhesus monkey. Psychol. Rep. 19: 823-828, 1966. 13. Shanab, M. E. and J. L. Peterson. Polydipsia in the pigeon. Psychon. ScL 15: 51-52, 1969. 14. Wilson, S. and W. B. Spencer. Schedule-induced polydipsia: Species limitations. Psychol. Rep. 36: 863-866, 1975.

Schedule-induced polydipsia in the guinea pig.

Physiology & Behavior, Vol. 19, pp. 573--575. Pergamon Press and Brain Research Publ., 1977. Printed in the U.S.A. BRIEF COMMUNICATION Schedule-Indu...
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