Different contribution of the lateral bed nucleus of the stria terminalis in intrahippocampal neostigmine-induced elevation of plasma glucose and adrenocorticotropic hormone in free moving rats.

OBJECTIVE: In our previous study, a lesion in the lateral bed nucleus of the stria terminalis (BNSTL) was found to significantly attenuate the elevation of adrenocorticotropic hormone (ACTH) in plasma during microinjectin of neostigmine, an inhibitor of acetylcholine esterase, into the rat hippocampus. The current study was designed to examine the role of the BNSTL in regulation of blood glucose elevation induced by hippocampal neostigmine injection.

MATERIALS AND METHODS: Ibotenic acid (15 microg/microl) was stereotaxically bilaterally injected into the BNSTL of rats. Two weeks after the injections, neostigmine methylsulfate (sigma, 5 x 10-8 mol) was microinjected into the rat hippocampus in a volume of 1 microl for 1 min using a CMA/100 microinjection pump. Plasma ACTH and glucose concentrations were examined using radioimmunoassay and immobilized enzyme casing/H2O2 method techniques, respectively.

RESULTS: Compared with sham-operated control rats, rats with BNSTL lesions produced by ibotenic acid showed significantly attenuated the elevations of plasma ACTH evoked by the microinjection of neostigmine into the hippocampus. However, no significant difference of blood glucose in response to the injection was observed between the BNSTL-lesioned rats and controls.

CONCLUSION: The results of the present study indicate that the BNSTL plays a role in ACTH regulation and not in blood glucose regulation when the hippocampal cholinergic system is activated.

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