AIMTo determine the effect of long-term inactivation of tyrosine kinases on voltage-gated calcium currents in pancreatic beta-cells and to evaluate the function of tyrosine kinases in pancreatic beta-cells.

METHODSPrimarily cultured mouse pancreatic islets and beta-cells were pretreated by 0.1 mmol/L genistein for 12 hours. Voltage-gated calcium currents and action potentials were recorded with patch clamp techniques in the configuration of perforated whole-cell recording. RT-PCR method was used to evaluate the changes in expression of voltage-gated calcium channels alpha1 subunit.

RESULTSAfter treatment by genistein for 12 hours, the whole-cell voltage-gated calcium currents were significantly diminished (-13.83 +/- 1.515 pA/pF vs. -7.012 +/- 1.502 pA/pF, P < 0.01, n=6). The amplitudes of action potentials in genistein-treated beta-cells were also significantly attenuated (38.50 +/- 7.46 mV vs. 15.95 +/- 4.39 mV, P < 0.01, n=6). The expression of voltage-gated calcium channels alpha1 subunit in mouse islets was significantly decreased to 0.792 +/- 0.078 of that in control conditions (P < 0.01, n=5).

CONCLUSIONGenistein treatment decreases expression and current of voltage-gated calcium currents in mouse pancreatic beta-cells, which suggests that inhibition of tyrosine kinases activity plays an important role in the dysfunction of pancreatic beta-cells.