Local electrographic effects of leu-enkephalin microinjections into the brain

Microinjections of Leu-enkephalin were made in dorsal hippocampus, caudate nucleus, amygdala, nucleus accumbens and parietal cortex in rats. The effects of enkephalin on the local electrical activity recorded from the area of the microinjection are described. Depression effects (attenuation of amplitudes and slowing) were recorded in caudate nucleus, nucleus accumbens, amygdala and parietal cortex, but not in hippocampus. Activation and epileptiform effects (spikes, seizures) were recorded from all structures studied.