Novel characteristics of ATP as a potential neuro-co-transmitter.

最近的研究结果证明，在肾上腺素能优势组织中，ATP能够与经典的递质去甲肾上腺素（NA）一起作为神经共递质。1986 - 1987年的研究项目旨在进一步阐明NA和ATP在豚鼠输精管中共传递的特征。第一年的HPLC-ECD研究表明，瓦巴因（100<micrn>）和/或monesin(10<micrn>)，而不是高KCI，产生了颗粒NA的显著释放，这是由细胞内Ca^<2+>介导的，可能来自线粒体储存位点。除了测量这个NA的释放。1987年的研究是用荧光计数法测量在分泌剂如瓦巴因加莫能菌素和高KCI存在下组织释放的ATP。瓦巴因加莫能菌素引起atp的适度流出，6-羟多巴胺和吡唑嗪显著减少了atp的流出，因此，这主要意味着核苷酸的神经元外释放。另一方面，6-羟多巴胺或Ca^<2+>-去除会大大降低高KCI对ATP的释放，但吡唑嗪不会，这表明主要是神经元ATP释放。高KCl对神经元ATP释放量的影响分别为1.7< micr> g/g湿重和11.2< micr> g/g湿重。另一方面，通过相同的程序，神经元NA的释放量分别为7.7<micrn>g /g和1.7<micrn>g/g湿重。这些结果有力地支持了一种可能性，即NA和ATP通过去极化和细胞内NA ^+水平的升高从肾上腺素能神经的两个不同存储位点共同释放。

Recent findings provide evidence that ATP is capable of acting as a neuro-co-transmitter along with the classical transmitter,noradrenaline(NA)in adrenergically dominant tissues.The research project from 1986 to 1987 was designed to clarify further characteristics of cotransmission of NA and ATP from guinea-pig vas deferens.The study with HPLC-ECD in the first year disignated that ouabain(100<micrn>and/or monesin(10<micrn>),but not high KCI,produced a prominent liberation of granular NA which was mediated by intracellular Ca^<2+> originating, presumably,from mitochondrial store sites.In addition to measuring this NA release.the investigation in 1987 was to measure ATP released from the tissue by a lumicounting method in the presence of secretagogues such as ouabain plus monensin and high KCI.Ouabain plus monensin caused a moderate outflow of atp which was markedly diminished by both 6-hydroxydopamine and prazosin,thus,meaning primarily an extraneuronal release of the nucleotide.On the other hand,an outstanding liberation of ATP by high KCI was highly decreased by 6-hydroxydopamine or Ca^<2+>-removal,but not by prazosin,indicating,mainly a neuronal ATP release.Amounts of neuronal release of ATP by ouabain plus monensin and by high KCl were 1.7<micrn>g and 11.2<micrn>g/g wet weight,respectively.On the other hand,that of neuronal release of NA by the same procedures amounted to 7.7<micrn>g and 1.7<micrn>g/g wet weight,respectively.These results strongly support a possibility that NA and ATP are co-released from two different store sites of the adrenergic nerves by depolarization and elevation of intracellular Na^+ levels.