[Central action of melanostatin and the opiate system of the brain].

The effects of intraventricular administration of melanostatin (MIF--I, Pro--Ley--Gly--NH2) on the behaviour and electrical activity in neocortex, amygdala, hippocampus and hypothalamus involved an enhancement of electrical activity: MIF enhanced the 3--7/sec high--voltage activity of neocortex, amygdala, hippocampus and the 7--12/sec one of neocortex. Morphine facilitated the effects of MIF whereas preliminary administration of MIF blocked the effect of threshold doses of morphine. After lesion of the central nucleus of amygdala the responsiveness of ipsilateral neocortex disappeared whereas that of hippocampus preserved.