Seizure-induced activation of enkephalin- and somatostatin-synthesizing neurons.

The extent of the neuronal network that is activated by kainic acid-induced seizures was anatomically identified and neurochemically characterized. Seizure-activated neurons were identified through the immunocytochemical demonstration of Fos protein in neuronal nuclei. These seizure-activated neurons were characterized by determining if they contained the mRNA for somatostatin or enkephalin, using in situ hybridization procedures. The results demonstrate that a majority of enkephalin- and somatostatin-synthesizing neurons expressed the Fos protein following seizures and that they represent a major component of the kainic acid-induced, seizure-activated neuronal network.