Are opioid peptides co-transmitters in noradrenergic vesicles of sympathetic nerves?
Are opioid peptides co-transmitters in noradrenergic vesicles of sympathetic nerves?
复制标题
阿片肽是交感神经去甲肾上腺素能囊泡中的共同递质吗？
作者：
Wilson,SP;Klein,RL;Chang,KJ;Gasparis,MS;Viveros,OH;Yang,WH
生物胺和肽类激素共存于Parkinone 1或胺前体摄取和脱羧（APUD）细胞2中。阿片肽荧光发生在肾上腺髓质的腺细胞和神经末梢中3，多巴胺β-羟化酶（EC 1.14.17.1）和脑啡肽样荧光发生在一些小的强荧光和交感神经节细胞中4。直接生物化学测定表明，阿片样肽（OLP），包括甲硫氨酸和亮氨酸脑啡肽在肾上腺髓质，并达到最高的比活性在纯化的肾上腺髓质嗜铬颗粒馏分5。嗜铬细胞也合成脑啡肽。肾上腺髓质从较大的物种，包括牛和人，包含更多的OLP材料比那些从较小的物种，如啮齿动物5，7;幸运的是，因为只有从牛是实际的纯化嗜铬颗粒和脾神经囊泡在颗粒纯度和产量适合化学成分的研究。在牛和人的血管、脾脏和输精管末端，大致密核心囊泡（LDV）占囊泡总数的30-50%，相当于总末端囊泡容量的80-90%。基于这些原因，我们选择牛脾神经来研究OLP在外周交感神经系统中的定位。我们的研究结果，报告在这里，并根据直接的生化分析，表明OLP，推定的递质和去甲肾上腺素可能共存于交感神经C-纤维，构成98%的牛脾神经。此外，OLP和去甲肾上腺素可能共存于该神经的大致密核心去甲肾上腺素能囊泡中。我们认为，阿片肽与去甲肾上腺素的摩尔比为1：60，这是迄今为止在任何神经递质细胞器或组织中脑啡肽的最高比例。
Biogenic amines and peptide hormones co-exist in paraneurones1or amine precursor uptake and decarboxylation (APUD) cells2. Opioid peptide immunohistofluorescence occurs in the gland cells and nerve endings of the adrenal medulla3, and both dopamineβ-hydroxylase (EC 1.14.17.1) and enkephalin-like immunohistofluorescence occurs in some small intensely fluorescent and sympathetic ganglion cells4. Direct biochemical assays demonstrate opiate-like peptides (OLPs) including Met- and Leu-enkephalin in the adrenal medulla, and the highest specific activity is attained in the purified adrenomedullary chromaffin granule fraction5. Chromaffin cells also synthesize enkephalinsde novo6. Adrenal medullae from larger species, including ox and man, contain much more OLP material than those from smaller species such as rodents5,7; fortunately so, because only from ox is it practical to purify both chromaffin granules and splenic nerve vesicles at particle purity and yield suitable for chemical composition studies. In ox and man the large dense-cored vesicles (LDVs) comprise 30–50% of the vesicle population in terminals of blood vessels, spleen and vas deferens, equivalent to 80–90% of the total terminal vesicle capacity. For these reasons, we chose bovine splenic nerve in which to investigate the localization of OLPs in the peripheral sympathetic system. Our results, reported here and based on direct biochemical analyses, indicate that OLPs, putative transmitters and noradrenaline probably coexist in sympathetic C-fibres, which constitute 98% of the bovine splenic nerve. Further, the OLPs and noradrenaline can probably co-exist in the large dense-cored noradrenergic vesicles of this nerve. We believe the obtained 1:60 molar ratio of opioid peptides:noradrenaline to be the highest yet demonstrated for enkephalins in any neurotransmitter organelle or tissue.