An operant determination of the behavioral mechanism of benzodiazepine enhancement of food intake
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A recent review paper by Cooper (Appetite 44:133–150, 2005) has pointed out that a role for benzodiazepines as appetite stimulants has been largely overlooked. Cooper’s review cited several studies that suggested the putative mechanism of enhancement of food intake after benzodiazepine administration might involve increasing the perceived pleasantness of food (palatability).
The present study examined the behavioral mechanism of increased food intake after benzodiazepine administration.
Materials and methods
The cyclic-ratio operant schedule has been proposed as a useful behavioral assay for differentiating palatability from regulatory effects on food intake (Ettinger and Staddon, Physiol Behav 29:455–458, 1982 and Behav Neurosci 97:639–653, 1983). The current study employed the cyclic-ratio schedule to determine whether the effects on food intake of chlordiazepoxide (CDP) (5.0 mg/kg), sodium pentobarbital (5.0 mg/kg), and picrotoxin (1.0 mg/kg) were mediated through palatability or regulatory processes.
The results of this study show that both the benzodiazepine CDP and the barbiturate sodium pentobarbital increased food intake in a manner similar to increasing the palatability of the ingestant, and picrotoxin decreased food intake in a manner similar to decreasing the palatability of the ingestant.
These results suggest that the food intake enhancement properties of benzodiazepines are mediated through a mechanism affecting perceived palatability.
KeywordsBenzodiazepines Barbiturates Palatability Cyclic-ratio Picrotoxin
This research was supported in part by the Wellcome Trust 063938/GM/KM/RL.
- Grill HJ, Norgren R (1978) The taste-reactivity test: I. Mimetic response to gustatory stimuli in neurologically normal rats. Brain Res Bull 143:263–279Google Scholar
- Higgs S, Cooper SJ (1995) Benzodiazepine receptor inverse agonists and ingestive behavior: the palatability hypothesis. In: Sarter M, Nutt DJ, Lister RG (eds) Benzodiazepine receptor inverse agonists. Wiley-Liss, New York, pp 163–184Google Scholar
- Meddis R (1975) A simple two-group test for matched scores with unequal cell frequencies. Br J Psychol 66:225–227Google Scholar
- Posadas-Andrews A, Burton MJ, Cooper SJ (1985) Chlordiazepoxide and food-depravation compared using a food-preference test in the rat. Rev Mex Anal Conducta 11:21–30Google Scholar