HIPPOCAMPAL CHOLINERGIC BLOCKADE ENHANCES HYPOTHALAMIC-PITUITARY-ADRENAL RESPONSES TO STRESS

We examined the role of the hippocampal cholinergic system, which is k nown to mediate processes related to fear and anxiety, in the regulati on of stress-induced hypothalamic-pituitary-adrenal (HPA) activity. Bi lateral intra-hippocampal injections (30 CLS per side) of the muscarin ic antagonist Scopolamine augmented adrenocorticotropin and corticoste rone responses to restraint without altering basal HPA activity compar ed to vehicle-treated animals. These results suggest that the hippocam pal cholinergic system regulates stress-induced HPA activity and may s erve to coordinate behavioral and neuroendocrine responses to stress. (C) 1997 Elsevier Science B.V.