Fawn hooded rats are subsensitive to the food intake suppressant effects of 5-HT agonists.

The food intake suppressant effects of three serotonin agonists, m-CPP (a selective 5-HT1B agonist), 8-OHDPAT (a selective 5-HT1A agonist) and fenfluramine (a 5-HT releasing agent) were compared in three different rat strains: Wistar, Sprague-Dawley (SD) and Fawn-Hooded (FH) rats. Administration of all three serotonin agonists produced dose-dependent decreases in 1 h food intake in all three strains. FH animals were significantly less sensitive to the food intake suppressant effects of all three serotonin agonists than either Wistar or SD rats. Body weight gain over the 9-week course of the study was also significantly less in FH animals than either Wistar or SD animals. These findings support some other data that Fawn Hooded rats, a strain with a peripheral platelet serotonin storage disorder, also possess altered central nervous system serotonergic function.