Effects of diazepam and of serotonin agonists on hyponeophagia in rats.

The effects of serotonin agonists, fenfluramine (2 mg/kg) and 5-methoxy N,N dimethyltryptamine (5-MeODMT, 2.5 mg/kg) on hyponeophagia were studied both alone and in combination with diazepam (1 mg/kg). Male and female rats were used but sex differences were not found. The serotonin agonists enhanced hyponeophagia while diazepam attenuated it and antagonised the actions of both serotonin agonists. These findings are discussed in connection with the serotonin hypothesis of benzodiazepine action with the conclusion that diazepam acts distally to serotonergic drugs on hyponeophagia.