Corticotropin-releasing factor modulates dietary preference in nutritionally and physically stressed rats

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Abstract
In order to evaluate the action of central nervous system Corticotropin-Releasing Factor (CRF) in the control of feeding behavior the present studies employed a dietary self-selection task sensitive both to overall appetite as well as preferential intake of familiar versus unfamiliar foods. Prior to the diet selection test, one group of nutritionally stressed animals was fed a protein deficient diet in order to increase the preference for unfamiliar foods relative to nutritionally replete subjects. Both CRF (0.05 and 0.5 µg ICV) and physical restraint (30 min) attenuated selectively the consumption of a novel food choice by deficient animals without affecting concurrent intake of familiar food. Further, CRF administration did not alter water intake or consumption of either diet by the replete control group suggesting that the peptide produced a stress dependent, enhanced response to novelty without a general effect on appetite. The CRF antagonist,α-helical CRF9–41 (1, 5 and 25 µg ICV), increased familiar diet consumption in nutritionally deficient subjects without affecting the self-selection pattern or replete controls. Chlordiazepoxide (5 mg/kg) also increased selectively the intake of familiar food suggesting that this action is the anxiolytic complement of the effect of stress in this paradigm. The CRF antagonist (5 and 25 µg) reversed the anorexia produced by CRF (0.5 µg) as well as that induced by restraint stress. These results favor a direct role for endogenous CRF systems in coordinating the behavioral responses to dietary stress.