INCREASED CORTICOTROPIN-RELEASING FACTOR IMMUNOREACTIVITY IN SELECT BRAIN SITES FOLLOWING KAINATE-ELICITED SEIZURES

The literature has focused on the localization, regulation and functio n of corticotropin-releasing factor (CRF)-expressing neurons localized in the paraventricular nucleus (PVN) of hypothalamus. However, less i nformation is available on the expression, regulation, and function of CRF at extrahypothalamic sites. The current study examined the induct ion of CRF in extrahypothalamic brain sites following generalized clon ic seizures induced by kainic acid. At 24 h post seizure onset, there was a marked increase of CRF immunolabeled perikarya in select brain a reas, which contained little, if any, CRF in control brains. This CRF- like labeling was observed in olfactory structures such as the main ol factory bulb (internal granular layer), anterior olfactory nucleus, an d deep layers of piriform cortex. Other sites of increased CRF-like im munoreactivity included the tenia tecta, inner layers of cingulate cor tex, lateral septum, dorsal endopiriform nucleus, fundus striatum, and nucleus of the lateral olfactory tract. Additionally, CRF-like labeli ng was atypically increased in the amygdala (lateral and basolateral a mygdaloid nuclei) and hippocampal formation (pyramidal cells of region s CA1/CA3 and polymorph cells within the dentate hilus). An associatio n between the increased CRF immunoreactivity and neuropathological pro cesses, characteristic of this seizure model, is hypothesized and disc ussed. (C) 1998 Elsevier Science B.V.