cAMP信号通路在5-羟色胺诱导硬壳蛤卵母细胞成熟过程中的作用

Function of cAMP signaling pathway in serotonin-induced oocyte maturation of hard clam Mercenaria mercenaria

采用体外药物诱导的方法,研究了5-羟色胺(5-HT)诱导的硬壳蛤(Mercenariamercenaria)卵母细胞成熟过程中 cAMP 信号通路的作用。结果表明,浓度为0.01～100μM的5-HT 均能够显著地诱导硬壳蛤卵母细胞的成熟,处理60min 时生发泡破裂(GVBD)发生率均可达到70%左右。不同浓度5-HT 的诱导作用表现出时间依赖性,但未表现出浓度依赖效应。咖啡因、茶碱和3-异丁基-1-甲基黄嘌呤(IBMX)可以单独抑制卵母细胞的自发成熟,但效果不显著。10mM 的咖啡因和茶碱以及5mM 的 IBMX 能够显著地抑制5-HT的诱导效果。1mM 的 IBMX 对5-HT 的诱导效果影响不显著,1mM 的咖啡因和茶碱能够促进5-HT 的诱导作用,但差异不显著。研究结果表明,cAMP 信号通路参与了5-HT 诱导的硬壳蛤卵母细胞的成熟过程,并且 cAMP 浓度的升高会抑制其成熟,cAMP 信号通路在硬壳蛤卵母细胞的成熟过程中可能起着负调控的作用。

To identify the function of cAMP signaling pathway in serotonin （5-HT）-induced oocyte maturation of hard clam, we investigated the effect of various modulators of transducers on oocyte maturation in hard clam in vitro. The results showed that 5-HT of 0.01 - 100μM induced the maturation of hard clam oocytes remarkably, and the GVBD rate of each concentration was about 70% after incubating for an hour. Moreover, the stimulation by 5-HT was time-dependent, but not does-dependent. Caffeine, theophylline and IBMX （inhibitors of phosphodiesterase） could inhibit spontaneous oocyte maturation slightly, but not significantly. High concentration of phosphodiesterase inhibitors （5mM IBMX, 10mM caffeine and 10mM theophylline） inhibited 5-HT-induced oocyte maturation significantly. However, lmM IBMX had no effect on 5-HT-induced maturation, whereas lmM caffeine and lmM theophylline could stimulate 5-HT-induced maturation slightly, but not remarkably. The results indicate that cAMP signaling pathway is invovled in 5-HT-induced oocyte maturation, and the rise of cAMP concentration can inhibit the maturation. In conclusion, cAMP signaling pathway plays probably a negative regulation role in 5-HT-induced oocyte maturation of hard clam.