ABSTRACT
Isolated freshly rat islets were transferred to 24-well plates and incubated with different concentrations of glucose or resveratrol for 1 or 24 h.The results showed that resveratrol dose-dependently inhibited glucose-stimulated insulin secretion from isolated rat islets after 1 h incubation,with 10%,35%,and 80% (P<0.05 or P<0.01) decrease at the concentrations of 1,I0,and 100 μmol/L.10 μmol/L resveratrol decreased the intracellular calcium concentration by 60% (P<0.05).After incubation for 24 h,resveratrol increased palmitatesuppressed insulin secretion to 75% (P<0.01) of control.These results suggest that resveratrol acutely inhibits insulin secretion from primary pancreatic islet via regulating intracellular calcium ion concentration,and in the long run resveratrol may protect β-cells from lipotoxicity.
ABSTRACT
AIM: To study the effects of sodium metabisulfite (SMB), sulfur dioxide (SO_2) and its derivatives in vivo, sodium bisulfite and sulfite, on Na~+ currents. The effects of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) against SMB were also studied in freshly dissociated hippocampal CA1 neurons in rats. METHODS: The whole-cell patch-clamp techniques were used in the experiments. RESULTS: ① SMB increased the voltage-activated Na~+ currents in a concentration-and voltage-dependent manner. The amplitudes of Na~+ currents was increased (22.36?3.28) % and (65.05?5.75)% (n=10) by SMB at 2 ?mol/L and 20 ?mol/L, respectively. ② SMB (10 ?mol/L) did not affect the activation process, but changed the inactivation process significantly. Before and after application of 10 ?mol/L SMB, the half-inactivation voltage was (-82.38)?0.54) mV and (-69.39)?0.41) mV (n=10, P
ABSTRACT
AIM and METHODS: The effects of hydrogen peroxide on Na+ currents were studied in freshly dissociated rat hippocampal CA1 neurons using the whole-cell patch-clamp techinique. RESULTS: 2貶 2O 2 caused a dose-dependent and voltage-dependent increase in the voltage-activated Na+ currents. The amplitudes of Na+ currents were increased (48.0?4.2)% and (88. 2?5. 1)% (n=10) by H 2O 2 at 10 ?mol/L and 100 ?mol/L, respectively. ②H 2O 2 (10 ?mol/L) did not affect the activation process, but changed the inactivation process significantly. Before and after application of 10 ?mol/L of H 2O 2, the half-inactivation voltage was (-64.58?1.22)mV and (-53.55?0.94)mV (n=10, P