Buspirone-induced carbohydrate feeding is not influenced by route of administration and nutritional status

Rats were habituated to ad lib food intake from two isoenergetic diets that differed in carbohydrate and protein content. To examine the route of administration effect, buspirone (0.6, 1.0, and 1.4 mg/kg) was injected into satiated rats either subcutaneously or intraperitoneally. Overall, no route of administration effect was observed; however, when results of the lowest dose were analyzed separately, the subcutaneous route was more effective than the intraperitoneal route. Regardless of route of administration, buspirone increased food intake over the first 2 h of food presentation in a dosedependent manner. Moreover, the increase was entirely attributed to increases in intake from the high carbohydrate diet. In the subsequent experiment, the effect of buspirone (0.6 mg/kg) was examined in both satiated (early light period) and nonsatiated rats (early dark period). Both groups responded to buspirone with an increase in carbohydrate intake. Despite differences in baseline intake, the absolute increase was similar between satiated and nonsatiated rats. These data suggest that both sensitivity and selectivity of buspirone-induced feeding are neither influenced by route of administration nor nutritional status of rats.