Calcium-dependent release of somatostatin and neurotensin from rat brain in vitro
Calcium-dependent release of somatostatin and neurotensin from rat brain in vitro
复制标题
大鼠脑体外生长抑素和神经降压素的钙依赖性释放
作者：
Leslie L. Iversen;Susan D. Iversen;Susan D. Iversen;Floyd E. Bloom;C. Douglas;Monica Brown;Wylie W. Vale
生长抑素和神经降压素最早是从哺乳动物下丘脑1-3的提取物中发现的。最近灵敏的放射免疫分析技术的发展和免疫组织化学研究的应用表明，这些多肽集中在中枢神经系统(CNS)4-12的不同区域的神经末梢。含有生长抑素的神经末梢在下丘脑的正中隆起特别丰富，生长抑素似乎是作为一种促垂体素释放出来的，控制着垂体前叶生长激素的分泌。生长抑素也存在于各种腺组织、胃肠道8、9和中枢神经系统中下丘脑4-6以外的许多区域的神经末梢中。神经降压素同样在下丘脑中高浓度存在，也存在于中枢神经系统的其他区域、胃肠道和脑下垂体10-12中。在中枢神经系统中，这些肽在特定的神经元系统中的独特定位表明，它们可能作为神经递质或神经调节剂释放，就像已提出的其他神经肽如P物质(REF)一样。13)和脑海豚14。然而，到目前为止，还没有证据表明生长抑素或神经降压素可以从中枢神经系统神经元中释放出来，尽管最近有报道说生长抑素在体外可以从神经垂体组织中释放出钙依赖性的生长抑素。在这里，我们描述了生长抑素和神经降压素在体外通过钙依赖的机制从大鼠脑组织中释放，从而进一步支持了这两种物质通常从中枢神经系统内的神经末梢释放的假说。
THE peptides somatostatin and neurotensin were first described in extracts of mammalian hypothalamus1–3. The recent development of sensitive radioimmunassay techniques and the application of immunohistochemical studies have shown that these peptides are concentrated in nerve terminals in various regions of the central nervous system (CNS)4–12. Somatostatin-containing nerve terminals are particularly abundant in the median eminence of the hypothalamus, from which somatostatin seems to be released as a hypophysiotropic hormone controlling the secretion of growth hormone from the anterior pituitary7. Somatostatin is also present in a variety of glandular tissues, in the gastrointestinal tract8,9, and in nerve terminals in many areas of the CNS outside the hypothalamus4–6. Neurotensin is similarly present in high concentration in the hypothalamus, and is also found in other areas of the CNS, in the gastrointestinal tract and in pituitary gland10–12. Within the CNS, the unique localisation of these peptides in specific systems of neurones suggests that they may be released as neurotransmitters or neuromodulators, as has been proposed for other neuropeptides such as substance P (ref. 13) and the enkephalins14. So far, however, it has not been shown that somatostatin or neurotensin can be released from CNS neurones, although a calcium-dependent release of somatostatin was recently reported from neurohypophyseal tissue in vitro15. We describe here the release of both somatostatin and neurotensin from rat brain tissue in vitro by a calcium-dependent mechanism, thus lending further support to the hypothesis that they may normally be released from nerve terminals within the CNS.