Gelerstein S, Shapira H, Dascal N, Yekuel R, Oron Y
Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Israel.
Dev Biol. 1988 May;127(1):25-32. doi: 10.1016/0012-1606(88)90185-6.
Acetylcholine rapidly lowered the intracellular levels of cyclic AMP in stage 5 and 6 Xenopus laevis oocytes. Acetylcholine alone did not induce oocyte maturation, though it did accelerate maturation induced by progesterone. The effect of acetylcholine on oocyte maturation was independent of extracellular calcium concentration. Adenosine increased cyclic AMP and abolished the progesterone-induced decrease in cyclic AMP levels in follicles and in denuded oocytes. This effect of adenosine was blocked by the Ra purinergic receptor antagonist, theophylline. Despite those effects, adenosine alone induced maturation in stage 6 oocytes and accelerated progesterone-induced maturation in both stage 5 and 6 cells. Adenosine also induced a significant increase in the rate of 45Ca efflux from oocytes in the presence and the absence of external calcium. We suggest that the activation of cell surface receptors involved in the release of calcium from cellular stores may induce or accelerate oocyte maturation independently of small changes in intracellular cyclic AMP concentration.
乙酰胆碱能迅速降低第5和第6期非洲爪蟾卵母细胞内的环磷酸腺苷（cAMP）水平。单独使用乙酰胆碱不会诱导卵母细胞成熟，不过它确实能加速孕酮诱导的成熟过程。乙酰胆碱对卵母细胞成熟的影响与细胞外钙浓度无关。腺苷能增加cAMP，并消除孕酮诱导的卵泡和去卵丘卵母细胞中cAMP水平的降低。腺苷的这种作用被嘌呤能受体拮抗剂茶碱所阻断。尽管有这些作用，但单独使用腺苷能诱导第6期卵母细胞成熟，并加速第5和第6期细胞中孕酮诱导的成熟过程。在有和没有细胞外钙的情况下，腺苷还能显著提高卵母细胞中45Ca的流出速率。我们认为，参与从细胞内储存释放钙的细胞表面受体的激活可能独立于细胞内环磷酸腺苷浓度的微小变化而诱导或加速卵母细胞成熟。
