Effect of restraint stress duration on macronutrient intake in the female rat

Research has revealed that different lengths of restraint stress may differentially influence food intake. These effects appear to be at least partially through corticosterone and possibly serotonergic mechanisms. Further, the deprivation state of the animal has been shown to alter serotonin (5-HT) activity and that elevated brain 5-HT levels decrease carbohydrate (CHO) and to some extent, fat intake in the rat. The following study investigates the effect of three different lengths of restraint stress (20 min, 2 h and 2 h/day chronically for 5 days) on macronutrient (CHO, protein, fat) intake in the female rat. Results indicate that while all three lengths of restraint inhibit fat and CHO intake, following 4 h of food deprivation, 24 h of food deprivation appears to attenuate the inhibition of CHO intake produced by either 20 min of restraint or chronic restraint but not that produced by 2 h of restraint. These data further the understanding of the effect of restraint stress and food deprivation on subsequent food intake by revealing effects on specific macronutrients. (C) 2002 Elsevier Science Inc. All rights reserved.