Department of Physiology, Institute of Endocrinology, Gunma University, Maebashi, Japan.
J Neuroendocrinol. 1989 Jun 1;1(3):209-14. doi: 10.1111/j.1365-2826.1989.tb00105.x.
Abstract To clarify the neural mechanism related to suppression of growth hormone (GH) secretion, biphasic electrical stimulation was delivered into several brainstem nuclei in the pentobarbital anaesthetized rat. A concentric bipolar stimulating electrode was implanted chronically one week prior to the electrical stimulation. Ninety min before the electrical stimulation, the rats were anaesthetized by ip injection of pentobarbital and a silastic cannula was inserted into the right atrium for blood sampling. Blood samples were withdrawn five times (0, 10, 20, 30 and 60 min) during the experiment. Electrical stimulation was delivered for 10 min just after the first blood sampling. One min after the onset of the stimulation, human GH-releasing hormone was injected iv to induce GH secretion. Electrical stimulation of several brainstem nuclei, i.e. the locus coeruleus, the rostral portion of the nucleus tractus solitarius and the lateral reticular nucleus suppressed GH secretion and the central gray of the pons showed a tendency for the suppression of GH secretion. On the other hand, electrical stimulation of the parabrachial nucleus and the caudal portion of the nucleus tractus solitarius did not suppress GH secretion. These suppressions were nullified by prior electrolytic lesioning of the hypothalamic periventricular nucleus where the major cell bodies of somatostatin immunoreactive fibres in the median eminence originate. These results indicate that electrical stimulation of several brainstem nuclei excites somatostatin neurons in the periventricular nucleus which are responsible for the suppression of GH secretion.
摘要 为了阐明与生长激素（GH）分泌抑制有关的神经机制，在戊巴比妥麻醉大鼠的脑干核团中给予双相电刺激。在电刺激前一周，将同心双极刺激电极慢性植入。在电刺激前 90 分钟，大鼠通过腹腔注射戊巴比妥麻醉，并将硅酮导管插入右心房进行采血。在实验过程中，共采集五次血样（0、10、20、30 和 60 分钟）。第一次采血后立即进行 10 分钟的电刺激。刺激开始后 1 分钟，静脉注射人 GH 释放激素以诱导 GH 分泌。刺激几个脑干核团，即蓝斑、孤束核的头端和外侧网状核，抑制 GH 分泌，桥脑中央灰区显示出抑制 GH 分泌的趋势。另一方面，刺激臂旁核和孤束核的尾端不会抑制 GH 分泌。这些抑制作用在预先用电解破坏室旁核后被消除，室旁核是正中隆起中生长抑素免疫反应纤维的主要细胞体起源的部位。这些结果表明，刺激几个脑干核团的电刺激兴奋了室旁核中的生长抑素神经元，这是抑制 GH 分泌的原因。
