α2- and β-adrenergic stimulation of corticosterone secretion in rats
Date
1993
Authors
Daniels W.M.U.
Jaffer A.
Russell V.A.
Taljaard J.J.F.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Bilateral injection of 6-hydroxydopamine into the medial forebrain bundle (MFB) significantly decreased monoamine concentrations in the hypothalamus. The noradrenaline and serotonin content of the paraventricular nucleus (PVN) was also significantly reduced. These drastic decreases in neurotransmitter concentration did not alter basal secretion of corticosterone. Isoproterenol, a β-adrenoceptor agonist (1 mg/kg, i.p.), significantly stimulated corticosterone release in saline and MFB lesioned rats. This stimulation did not differ significantly between the two groups. Clonidine, an α2- adrenoceptor agonist, injected either intraperitoneally or intracerebrally just dorsal to the PVN, caused a dose-dependent increase in corticosterone secretion. The stimulation of corticosterone release by clonidine (250 μg/kg, i.p.) was antagonised by the selective α2-adrenoceptor antagonist, yohimbine (1 mg/kg, i.p.) and significantly reduced by the MFB lesion. These results suggest that corticosterone secretion is stimulated by activation of α2-adrenoceptors which occur on noradrenergic nerve terminals in the PVN.
Description
Keywords
alpha 2 adrenergic receptor, beta adrenergic receptor, clonidine, corticosterone, isoprenaline, monoamine, noradrenalin, oxidopamine, serotonin, yohimbine, alpha adrenergic stimulation, animal experiment, animal tissue, article, beta adrenergic stimulation, controlled study, corticosterone blood level, corticosterone release, hypothalamus, male, medial forebrain bundle, nonhuman, noradrenalin brain level, noradrenergic nerve, priority journal, rat, serotonin brain level, thalamus midline nucleus, Animal, Clonidine, Corticosterone, Male, Rats, Rats, Wistar, Receptors, Adrenergic, alpha, Receptors, Adrenergic, beta, Support, Non-U.S. Gov't, Yohimbine, Animalia
Citation
Neurochemical Research
18
2
18
2