EFFECTS OF GENERALIZED CONVULSIVE SEIZURES ON CORTICOTROPIN-RELEASINGFACTOR NEURONAL SYSTEMS

Most stressors generate a set of endocrine and neural adaptations that form a stress response. The corticotropin-releasing factor neurons of the paraventricular nucleus of hypothalamus integrate endocrine and n eural inputs, and cause a cascade of events with resultant increased l evels of pituitary adrenocorticotropic hormone and adrenal hormones. A lthough activation of the hypothalamic-pituitary-adrenal axis is assoc iated with a large variety of stressors, the effects of seizures on hy pothalamic corticotropin-releasing factor neurons are essentially unkn own. The gaol of the present study was to elucidate the effects of gen eralized convulsive seizures on distinct and separate corticotropin-re leasing factor cell populations in brain. Seizure-activated neurons we re identified immunocytochemically through their expression of the Fos protein. Seizures were induced by intraperitoneal injection of kainic acid. In the paraventricular nucleus, the vast majority of corticotro pin-releasing factor-like parvocellular neurons also expressed Fos-lik e protein following seizure elicitation. This response was specific to corticotropin-releasing factor neurons of the paraventricular nucleus , as corticotropin-releasing factor neurons in central nucleus of the amygdala or bed nucleus of the stria terminalis did not simultaneously localize Fos following seizures.