Nadler E, Gillo B, Lass Y, Oron Y
FEBS Lett. 1986 Apr 21;199(2):208-12. doi: 10.1016/0014-5793(86)80481-1.
Acetylcholine induces a complex electrical membrane response in Xenopus laevis oocytes. This response is mimicked, and probably mediated by injected inositol 1,4,5-trisphosphate. Oocytes prelabelled with 45Ca released calcium in two phases, the second, slow phase exhibiting first order kinetics of release. Brief exposure of prelabelled oocytes to acetylcholine resulted in a significant increase in the rate of calcium release that returned to control values 2-3 min following the removal of the neurotransmitter. Intracellular injection of inositol 1,4,5-trisphosphate resulted in increased rate of calcium release similar to, but longer than that caused by acetylcholine. Experiments conducted on single oocytes permitted the investigation of the relationship between acetylcholine-induced and inositol 1,4,5-trisphosphate-induced calcium mobilization and the resulting electrical membrane response. Our data reinforce our previous suggestion that inositol 1,4,5-trisphosphate is the intracellular second messenger of the muscarinic membrane electrical response in Xenopus oocytes.
乙酰胆碱可诱导非洲爪蟾卵母细胞产生复杂的电膜反应。这种反应可被注入的肌醇1,4,5 -三磷酸模拟，并且可能由其介导。预先用45Ca标记的卵母细胞分两个阶段释放钙，第二个缓慢阶段呈现一级释放动力学。预先标记的卵母细胞短暂暴露于乙酰胆碱会导致钙释放速率显著增加，在去除神经递质后2 - 3分钟恢复到对照值。细胞内注射肌醇1,4,5 -三磷酸会导致钙释放速率增加，类似于乙酰胆碱引起的，但持续时间更长。在单个卵母细胞上进行的实验允许研究乙酰胆碱诱导的和肌醇1,4,5 -三磷酸诱导的钙动员之间的关系以及由此产生的电膜反应。我们的数据强化了我们之前的观点，即肌醇1,4,5 -三磷酸是非洲爪蟾卵母细胞中毒蕈碱膜电反应的细胞内第二信使。
