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目的 观察阿片激动剂急性和长时程作用于稳定表达 i NOS基因的 NG- L NCXi NOS细胞 ,对细胞内游离钙 ([Ca2 + ]i)的影响及 G-蛋白的调节作用。方法 应用共聚焦显微镜和荧光探针 Fluo- 3,监测单细胞 [Ca2 + ]i 含量变化。结果 δ-阿片激动剂 DPDPE和吗啡急性刺激细胞诱发 [Ca2 + ]i 增加 ,纳洛酮对其起翻转作用 ;用百日咳毒素预处理细胞后 ,吗啡急性刺激不能引起 [Ca2 + ]i 增加 ;DPDPE和吗啡长时程处理细胞 ,再用相应的阿片激动剂急性刺激也造成 [Ca2 + ]i 增加 ,但 [Ca2 + ]i 增加水平较低 ,用纳洛酮戒断造成 [Ca2 + ]i 明显增加。结论 阿片激动剂诱发[Ca2 + ]i 增加是由阿片受体介导的 ,受对 PTX敏感的 G-蛋白调节 ,当细胞发生阿片耐受和依赖时 ,表现为受体介导 Ca2 + 系统的脱敏现象。
Objective To observe the effect of opiate agonist on the expression of iNOS gene in NG-L NCXi NOS cells induced by acute and long-term exposure to intracellular free calcium ([Ca2 +] i) and the regulation of G-protein. Methods Confocal microscopy and fluorescent probe Fluo-3 were used to monitor the changes of [Ca2 +] i in single cells. RESULTS: The [Ca2 +] i induced by δ-opioid agonist DPDPE and morphine acute stimulated cells increased, and naloxone reversed the effect. After pretreatment of cells with pertussis toxin, acute stimulation of morphine did not induce [Ca2 +] i increase; DPDPE And morphine prolonged treatment of cells, and then the corresponding opiate agonist acute stimulation also caused [Ca2 +] i increased, but [Ca2 +] i increased the level of low, with naloxone withdrawal caused by [Ca2] i significantly increase. CONCLUSION: The increase of [Ca2 +] i induced by opioid agonists is mediated by opioid receptors and is regulated by PTX-sensitive G-protein. When the cells undergo opioid tolerance and dependence, they show receptor-mediated Ca2 + system Desensitization phenomenon.