Intracerebral injection of different antibodies against endogenous opioids suggests alpha-neoendorphin participation in control of feeding behaviour.

The mechanism of feeding behaviour of rats was examined. We used antibodies to different opioid peptides in order to reduce the tonic activity of various endogenous opioid peptide systems that may underly appetite. Unilateral microinjection of anti-alpha-neoendorphin antibodies into various areas of the ventromedial hypothalamus (VMH) inhibited food and water intake up to 45% in deprived animals. Injections outside this area failed to affect feeding. Administration of anti-beta-endorphin antibodies into the VMH moderately attenuated appetite. A considerable decrease of food and water intake was observed only upon injection of this antibody into the nucleus periventricularis hypothalami, a region generally believed to be involved with feeding. A marginal reduction of appetite was observed with anti-dynorphin antibodies injected into the VMH. These data may suggest that alpha-neoendorphin is involved in the control of food and water intake in the VMH.