RESUMO
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.
