The effects of amylin on the islet β-cells voltage-gated L-calcium channels in rats / 中华内科杂志

ABSTRACT

Objective To observe the effect of amylin on the islet β-cells voltage-gated L-calcium channels in rats. Method Patch clamp technique was employed in the observation of the features and changes of electric current of islet β-cells voltage-gated L-calcium channels before and after using amylin. Results In the glucose environment of 5. 5 mmoL/L, the electric current of rat islet β-cells voltage-gated L-calcium channels was activated at-40 mV and reached the peak at about +20 mV, with a peak value of about-120 pA and the insulin secretion level was(0. 76±0. 12) μg/L. Under the stimulation of glucose of 16. 7 mmol/L, the peak current voltage moved to the left and increased up to-140 pA and the level of insulin secretion measured (1.78±0. 13) μg/L. Hatch islet β-cells in amylin at the concentrations of 0. 5, 1.0, 5.0 and 10.0 μmol/L, respectively. It was observed that in the 0. 5 μmol/L and 1.0 μmol/L groups,there was no remarkable change in the peak potential activation voltage, current, and insulin secretion volume in comparison with the control group. However, in the environment of 5.5 mmol/L glucose, the increase of activation voltage of the 5.0 and 10.0 μmol/L groups was-30 mV, with the peak current reduced to approximately-80 pA and-60 pA and the insulin secretion decreased to (0. 49±0. 11) μg/L and (0. 36±0. 12) μg/L respectively. Under the concentration of 16. 7 mmol/L glucose, the activation voltage increased from-40 mV up to-30 mV and the peak current reduced to-80 pA and-40 pA. In the meantime, the insulin secretion decreased respectively to (1.20±0. 13) μg/L and (0. 89±0. 14) μg/L, which is of significance. Conclusion The secretion of insulin is synchronized with the opening of the islet β-cells voltage-gated L-calcium channels at the stimulation of glucose. The amylin inhibition of the insulin secretion is also synchronized with the opening of islet β-cells voltage-gated L-calcium channels and it's in a positive concentration-dependent manner.