Involvement of endogenous enkephalins in the feeding response to diazepam.

The effect of the delta-opioid agonist [D-Ala2,D-Leu5]enkephalin (DADLE) and the benzodiazepine diazepam on the food intake of non-deprived rats was investigated. Both compounds produced a significant increase in feeding. The hyperphagic response to DADLE (10 micrograms i.c.v.) and diazepam (1 mg/kg i.p.) was suppressed by concurrent treatment with the selective delta-opioid antagonist ICI 154,129 (10 micrograms i.c.v.). These findings add further support to the concept that endogenous enkephalins may be implicated in the stimulatory effects of benzodiazepines on ingestive behaviour.