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

最近的发现表明，在肾上腺素占优势的组织中，ATP能够与经典的递质去甲肾上腺素(NA)一起起到神经协同递质的作用。1986-1987年的研究项目旨在阐明NA和ATP从豚鼠输精管共传递的进一步特征。第一年的高效液相-电子捕获检测器研究表明，哇巴因(100；microrn&gt；和/或monesin(10&lt；microrn&gt；))，但不是高KCI，产生了显著的颗粒状NA的释放，这是由细胞内钙调节的。除了测量这种NA的释放外，1987年的调查是在诸如哇巴因加莫能菌素和高KCI等分泌剂存在的情况下，用发光计数法测量组织释放的ATP。哇巴因加莫能菌素引起组织中适度的ATP外流，这一流出显著地被6-羟基多巴胺和哌唑嗪所抑制，因此，这主要意味着核苷酸的神经元外释放。另一方面，高KCI显著释放的ATP被6-羟基多巴胺或钙离子大大减少。哇巴因加莫能菌素和高钾对神经元的ATP释放量分别为1.7微克和11.2微克/克湿重。另一方面，神经元对NA的释放量分别为7.7微克和1.7微克。这些结果有力地支持了NA和ATP通过去极化和细胞内Na~+水平升高而从肾上腺素能神经的两个不同存储位置共同释放的可能性。

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.