中文摘要：

目的 研究多巴胺（dopamine,DA）对大鼠胰岛素分泌的影响及可能机制。方法 ♂SD大鼠的胰腺经过胶原酶P消化、Histopaque 1077梯度离心后得到纯化的胰岛,DispaseⅡ将胰岛消化为单个细胞。应用胰岛素分泌实验来验证DA对胰岛素分泌的作用,通过膜片钳技术和钙成像技术记录β细胞内向性钙电流、动作电位时程和细胞内Ca2＋浓度,研究DA对大鼠胰岛素分泌的作用机制。结果 在2.8mmol·L^-1的葡萄糖中,DA对胰岛素的分泌没有产生明显的影响;在16.7mmol·L^-1的葡萄糖中,DA呈浓度依赖性抑制胰岛素的分泌。DA干预后,抑制了胰岛β细胞上内向性钙电流,缩短动作电位时程,减少了细胞内Ca2＋浓度。结论 DA通过抑制β细胞上内向性钙电流,进而缩短了动作电位的时程,降低细胞内Ca2＋浓度,最终抑制胰岛素的分泌。

英文摘要：

Aim To investigate the effects of dopamine（DA）on insulin secretion from rat islets and the possible mechanism.Methods Pancreatic islets were obtained from the pancreatic of male SD rats by collagenase P digestion and histopaque-1077 density gradient separation.Insulin secretion experiment was used to observe the change of insulin release after DA treatments.As to study the potential mechanisms of the effects of DA, patch-clamp experiment and calcuim image technique were applied to test the depolarization-evoked Ca2＋ currents, action potential duration and intracellular Ca2＋ concentration.Results In 2.8 mmol·L^-1 glucose, DA had no effect on insulin secretion; in 16.7 mmol·L^-1 glucose, dopamine inhibited insulin secretion in a dose-dependent manner.DA inhibited the inward calcium current, shorten the action potential duration, and reduced the intracellular Ca2＋ concentration.Conclusion DA inhibits insulin secretion maybe by decreasing the inward calcium current leading to shorten the action potential duration and reduce the intracellular Ca2＋ concentration.