Petit P, Manteghetti M, Puech R, Loubatieres-Mariani M M
Biochem Pharmacol. 1987 Feb 1;36(3):377-80. doi: 10.1016/0006-2952(87)90297-8.
Our previous experiments on isolated rat pancreas gave evidence for a P2 purinergic receptor on the insulin-secreting B cell. This work was designed to investigate whether the stimulation of insulin release by phosphorylated adenosine derivatives could also be observed in rat isolated Langerhans islets and whether this stimulation was accompanied by changes in calcium uptake. The results indicate that two structural methylene analogues of ATP and ADP (alpha,beta-methylene ATP and alpha,beta-methylene ADP) display an insulin stimulatory effect comparable to that of ATP, confirming the membrane action of the latter. It was also found that calcium uptake increased concomitantly with insulin release under the effect of alpha,beta-methylene ADP; on the other hand this agent also increased the total exchangeable calcium content of islets at isotopic equilibrium. Verapamil, a blocker of voltage-sensitive calcium channels, counteracted the stimulation of insulin release and also blocked the increase in total exchangeable calcium content. These results demonstrate the involvement of calcium in the stimulus-secretion coupling of insulin release induced by an activator of P2 purinergic receptors and suggest the implication of voltage-sensitive calcium channels.
我们之前对大鼠离体胰腺进行的实验证明，胰岛素分泌β细胞上存在P2嘌呤能受体。本研究旨在探究磷酸化腺苷衍生物对胰岛素释放的刺激作用是否也能在大鼠离体胰岛中观察到，以及这种刺激是否伴随着钙摄取的变化。结果表明，ATP和ADP的两种结构亚甲基类似物（α,β-亚甲基ATP和α,β-亚甲基ADP）具有与ATP相当的胰岛素刺激作用，证实了后者的膜作用。还发现，在α,β-亚甲基ADP的作用下，钙摄取与胰岛素释放同时增加；另一方面，该试剂在同位素平衡时也增加了胰岛的总可交换钙含量。电压敏感性钙通道阻滞剂维拉帕米可抵消胰岛素释放的刺激作用，并阻断总可交换钙含量的增加。这些结果证明了钙参与了P2嘌呤能受体激活剂诱导的胰岛素释放的刺激-分泌偶联，并提示了电压敏感性钙通道的作用。
