Involvement of the bed nucleus of the stria terminalis in hippocampal cholinergic system-mediated activation of the hypothalamo-pituitary-adrenocortical axis in rats

This study was designed to determine the effect of the bed nucleus of the s tria terminalis (BNST) in hippocampal cholinergic system-mediated activatio n of the hypothalamo -pituitary- adreno cortical (HPA) axis in the rat. Neu rons in the BNST were lesioned by bilateral injection of the cell-selective neurotoxin, ibotenic acid (1.5 mug/mul of solution per side). Two weeks la ter, neostigmine was microinjected into the rats' hippocampus. Rats in whic h ibotenic acid had been injected into the. BNST showed attenuated expressi on of c-Fos in the hypothalamic paraventricular nucleus (PVN) and blunted e levation of plasma adrenocorticotropic hormone (ACTH) after microinjection of neostigmine into the hippocampus compared with rats in which saline had been injected into the BNST. The results of this study indicate that the BN ST relays signals of hippocampal cholinergic system-mediated activation of the HPA axis in rats. (C) 2001 Elsevier Science B.V. All rights reserved.