Effects of sibutramine and rimonabant in rats trained to discriminate between 22- and 2-h food deprivation.
OBJECTIVE
The objective of the study was to evaluate whether sibutramine and rimonabant, drugs that decrease food intake in human and non-human animals, affect the discriminative stimulus effects associated with acute food deprivation ("hunger").


METHODS
Rats were trained to discriminate between 22- and 2-h food deprivation in a two-lever choice procedure. After rats acquired the discrimination, subjects were food-restricted for 22 h and administered with sibutramine (0.32-10 mg/kg, p.o.) or rimonabant (0.32-10 mg/kg, s.c.) before a generalization test session.


RESULTS
Sibutramine (3.2 mg/kg) produced significant decreases in 22-h deprivation-appropriate responding, response rates (resulting in lever pressing rates similar to those following 2-h food deprivation), and food intake measured 1 h after the generalization test. A larger sibutramine dose eliminated responding and significantly reduced food intake. Rimonabant did not alter the discriminative stimulus effects of 22-h food deprivation, but rimonabant did significantly reduce both response rates and food intake.


CONCLUSIONS
Sibutramine appears to decrease food intake by reducing hunger sensations associated with food deprivation. In contrast, rimonabant does not alter the discrimination of acute food deprivation. The use of food-deprivation discrimination techniques may be useful in identifying the role of specific neuroactive compounds in eating stimulated by a sense of hunger and may aid in medication development for more effective treatments for obesity and other eating-related conditions.
Jewett
David C
DC
Department of Psychology, University of Wisconsin-Eau Claire, Eau Claire, WI, USA. jewettd@uwec.edu
Hahn
Thomas W
TW
Smith
Travis R
TR
Fiksdal
Britta L
BL
Wiebelhaus
Jason M
JM
Dunbar
Andrew R
AR
Filtz
Catherine R
CR
Novinska
Noah L
NL
Levine
Allen S
AS
D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology*; D003503:Cyclobutanes / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D004435:Eating / Q000187:drug effects*; D005508:Food Deprivation; D008297:Male; D010880:Piperidines / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077285:Rimonabant; D013997:Time Factors
D001067:Appetite Depressants; D003503:Cyclobutanes; D010880:Piperidines; D011720:Pyrazoles; D000077285:Rimonabant; C058254:sibutramine