Daniels W M, Jaffer A, Russell V A, Taljaard J J
Department of Chemical Pathology, University of Stellenbosch, Tygerberg Hospital, Republic of South Africa.
Neurochem Res. 1993 Feb;18(2):159-64. doi: 10.1007/BF01474679.
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 beta-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 alpha 2-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 micrograms/kg, i.p.) was antagonised by the selective alpha 2-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 alpha 2-adrenoceptors which occur on noradrenergic nerve terminals in the PVN.
将6-羟基多巴胺双侧注射到内侧前脑束（MFB）中可显著降低下丘脑的单胺浓度。室旁核（PVN）中的去甲肾上腺素和5-羟色胺含量也显著降低。神经递质浓度的这些急剧下降并未改变皮质酮的基础分泌。异丙肾上腺素，一种β-肾上腺素能受体激动剂（1毫克/千克，腹腔注射），在生理盐水处理的大鼠和MFB损伤的大鼠中均显著刺激皮质酮释放。两组之间这种刺激没有显著差异。可乐定，一种α2-肾上腺素能受体激动剂，经腹腔注射或在PVN背侧脑内注射，可引起皮质酮分泌呈剂量依赖性增加。可乐定（250微克/千克，腹腔注射）对皮质酮释放的刺激作用被选择性α2-肾上腺素能受体拮抗剂育亨宾（1毫克/千克，腹腔注射）拮抗，且MFB损伤使其显著降低。这些结果表明，皮质酮分泌受到PVN中去甲肾上腺素能神经末梢上α2-肾上腺素能受体激活的刺激。
