GABA acts directly on cells of pituitary pars intermedia to alter hormone output
GABA acts directly on cells of pituitary pars intermedia to alter hormone output
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GABA 直接作用于垂体中间部细胞以改变激素输出
DOI：
10.1038/301706a0
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发表时间：
1983
期刊：
影响因子：
64.8
通讯作者：
William W. Douglas
中科院分区：
文献类型：
--
作者：
S. A. Tomiko;P. S. Taraskevich;William W. Douglas
最近从大鼠免疫组织化学证据表明，γ-氨基丁酸（GABA）含有纤维的中枢神经起源项目的垂体中间部1，2，提示调查这种神经支配的功能。有电生理学证据表明，GABA通过荷包牡丹碱可阻断的受体直接作用于从大鼠分离的促黑素细胞，增加Cl−电导，从而驱动这些细胞的膜电位向Cl−平衡电位移动，导致静息时的去极化或过量K+引起的去极化减少（参考文献3）。由于电压依赖性Ca通道可以参与这些细胞分泌的调节4，我们现在已经检查了GABA对激素输出的影响，发现它首先刺激然后抑制促黑素细胞激素（MSH）的自发分泌，并抑制K+诱发的分泌。此外，我们的药理学证据表明，类似的受体参与分泌和电生理反应。因此，GABA能神经支配的功能可能是通过直接作用于黑素营养细胞来调节激素输出，并且这种调节可能受到GABA诱导的电特性变化的影响。
Recent immunohistochemical evidence from the rat, indicating that γ-aminobutyric acid (GABA)-containing fibres of central nervous origin project to the pars intermedia of the pituitary1,2, prompts inquiry into the function of this innervation. There is electrophysiological evidence that GABA acts directly on melanotrophs isolated from rat, through bicuculline-blockable receptors, to increase Cl− conductance and thereby drive the membrane potential towards the Cl− equilibrium potential in these cells, resulting in depolarization at rest or reduction of the depolarization caused by excess K+ (ref. 3). As voltage-dependent Ca channels can participate in the regulation of secretion in these cells4, we have now examined the effect of GABA on hormone output and find that it first stimulates and then inhibits spontaneous secretion of melanocyte-stimulating hormone (MSH) and inhibits K+-evoked secretion. Moreover, our pharmacological evidence suggests that similar receptors are involved in the secretory and the electrophysiological responses. A function of the GABAergic innervation may therefore be to regulate hormone output by acting directly on the melanotrophs, and this regulation may be affected by the changes in electrical properties induced by GABA.