Stimulation of ingestive behaviors following injections of excitatory amino acid antagonists into the median raphe nucleus.

Anatomical and pharmacological evidence suggests that excitatory amino acids (EAA's) may function as neurotransmitters within the median raphe nucleus (MR). Previous studies have shown that injections of EAA antagonists into the MR result in marked hyperactivity. The current report extends these findings by demonstrating that intra-raphe injections of two EAA antagonists, kynurenic acid and 2-amino-5-phosphonovaleric acid, result in dose-dependent increases in food and water intake in nondeprived rats. These results suggest that EAA's within the MR may play a role in the control of appetitively motivated behaviors.