Meffert M K, Premack B A, Schulman H
Department of Neurobiology, Stanford University School of Medicine, California 94305-5401.
Neuron. 1994 Jun;12(6):1235-44. doi: 10.1016/0896-6273(94)90440-5.
A new fluorescence method using the dye FM1-43 was used to examine exocytotic release from hippocampal synaptosomes. Nitric oxide caused a marked transient stimulation of vesicle release. Several structurally unrelated nitric oxide donors, sodium nitroprusside, S-nitroso-N-acetylpenicillamine, 3-morpholino-sydnonimine, and acidified sodium nitrite, were effective. Release stimulated by nitric oxide and KCl were comparable in time course, using both the fluorescence assay and [3H]L-glutamate to monitor neurotransmitter release. Activation of guanylyl cyclase was not responsible for nitric oxide-stimulated release. Unlike release stimulated by KCl or A23187, nitric oxide-stimulated release was found to be independent of a rise in intrasynaptosomal Ca2+. Indo-1/AM measurements indicated that nitric oxide actually decreased intracellular Ca2+, and the Ca2+ channel blocker Cd2+ did not affect nitric oxide-stimulated vesicle release. Nitric oxide does, however, appear to act on the Ca(2+)-sensitive pool of vesicles. Nitric oxide may be the first physiological mediator that induces vesicle exocytosis without raising Ca2+ and may provide an interesting new tool for the study of molecules involved in vesicle exocytosis.
一种使用染料FM1-43的新型荧光方法被用于检测海马突触体的胞吐释放。一氧化氮引起了囊泡释放的显著短暂刺激。几种结构不相关的一氧化氮供体，硝普钠、S-亚硝基-N-乙酰青霉胺、3-吗啉代-西多尼明和酸化亚硝酸钠，都具有效果。使用荧光测定法和[3H]L-谷氨酸来监测神经递质释放时，一氧化氮和氯化钾刺激的释放在时间进程上是可比的。鸟苷酸环化酶的激活与一氧化氮刺激的释放无关。与氯化钾或A23187刺激的释放不同，一氧化氮刺激的释放被发现与突触体内Ca2+的升高无关。Indo-1/AM测量表明一氧化氮实际上降低了细胞内Ca2+，并且Ca2+通道阻滞剂Cd2+不影响一氧化氮刺激的囊泡释放。然而，一氧化氮似乎作用于对Ca(2+)敏感的囊泡池。一氧化氮可能是第一种在不升高Ca2+的情况下诱导囊泡胞吐的生理介质，并且可能为研究参与囊泡胞吐的分子提供一个有趣的新工具。
