Elicitation of feeding, drinking, and gnawing following microinjections of muscimol into the median raphe nucleus of rats.

Previous studies have demonstrated that injections of muscimol into the median raphe nucleus (MR) result in large increases in locomotor activity and food intake. The current experiment extends these results by showing that intra-MR muscimol injections in nondeprived rats also elicit nonprandial drinking and gnawing of wooden blocks. These findings indicate that stimulation of GABA receptors within the MR is able to energize a wide range of oral behaviors and is compatible with the view that the MR may be part of a "nonspecific" behavioral activation system.