Livett B G, Dean D M, Whelan L G, Udenfriend S, Rossier J
Nature. 1981 Jan 22;289(5795):317-9. doi: 10.1038/289317a0.
The opioid peptides Leu-enkephalin and Met-enkephalin are stored intraneuronally in the brain where they are thought to act as neurotransmitters and/or neuromodulators. Evidence for their release from nerve terminals has come from biochemical and pharmacological studies in vitro with brain tissue slices and synaptosomes. Enkephalins also exist in the peripheral nervous system in nerve cell bodies and axon terminals in the gastrointestinal tract, sympathetic ganglia and adrenal gland. In the adrenal gland, high levels of enkephalins are present both in axon terminals of the splanchnic nerve and in the adrenal medullary chromaffin cells where they are stored together with the catecholamines in the chromaffin granules. Stimulation of the adrenal gland in vivo or the perfused gland in vitro causes release of catecholamines and enkephalins into the adrenal vein. However, it is not clear whether the origin of the released enkephalins is the adrenal medullary chromaffin cells or the enkephalin-containing splanchnic nerve terminals that innervate the medulla. We now show that enkephalin and catecholamines are released together from primary cultures of bovine adrenal medullary chromaffin cells by nicotine in a Ca2+-dependent manner.
阿片肽亮氨酸脑啡肽和甲硫氨酸脑啡肽储存于脑内的神经元中，被认为在其中作为神经递质和/或神经调质发挥作用。它们从神经末梢释放的证据来自于对脑组织切片和突触体进行的体外生化和药理学研究。脑啡肽在周围神经系统的神经细胞体以及胃肠道、交感神经节和肾上腺的轴突终末中也有存在。在肾上腺中，内脏神经的轴突终末和肾上腺髓质嗜铬细胞中都存在高水平的脑啡肽，它们与儿茶酚胺一起储存在嗜铬颗粒中。体内刺激肾上腺或体外灌注肾上腺会导致儿茶酚胺和脑啡肽释放到肾上腺静脉中。然而，尚不清楚释放的脑啡肽的来源是肾上腺髓质嗜铬细胞还是支配髓质的含脑啡肽的内脏神经末梢。我们现在表明，尼古丁以钙离子依赖的方式从牛肾上腺髓质嗜铬细胞的原代培养物中共同释放脑啡肽和儿茶酚胺。
