Effect of Cu 2+ on K + Current in Acutely Isolated Rat Hippocampal Neurons by Whole Cell Patch Clamp Technique

Using the whole cell patch clamp technique, the effect of Cu 2+ on transient outward K + current ( I to ) and delayed rectifier K + current ( I dr ) was studied in acutely isolated rat hippocampal neurons. I to and I dr were increased when the concentration of Cu 2+ was lower than 2×10 −5 and 10 −5 mol/L, respectively, and increased ratio was decreased with increasing Cu 2+ concentration in the bath solutions. When the concentration continued to increase to 5×10 −5 and2×10 −5 mol/L, the currents were hardly changed, while the concentration was more than 10 −4 and 5×10 −5 mol/L, the currents were inhibited remarkably. Cu 2+ (10 −5 mol/L) did not affect the activation and inactivation process of I to . The activation curve of I dr was shifted toward positive potential, but 10 −5 mol/L Cu 2+ did not affect slope factor. According to these results, it was considered that Cu 2+ at low concentration in the bath solution could promote I to and I dr while at high concentration could inhibit them, and change of amplitude was different with different membrane voltage. Conclusion was drawn: Cu 2+ may be involved in the pathophysiologic mechanism of diseases with neuropathological components.