Effect of Cu2+ on K+ Current in Acutely Isolated Rat Hippocampal Neurons by Whole Cell Patch Clamp Technique

Abstract

Using the whole cell patch clamp technique, the effect of Cu2+ on transient outward K+ current (Ito) and delayed rectifier K+ current (Idr) was studied in acutely isolated rat hippocampal neurons. Ito and Idr were increased when the concentration of Cu2+was lower than 2×10−5 and 10−5 mol/L, respectively, and increased ratio was decreased with increasing Cu2+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. Cu2+ (10−5 mol/L) did not affect the activation and inactivation process of Ito. The activation curve of Idr was shifted toward positive potential, but 10−5 mol/L Cu2+ did not affect slope factor. According to these results, it was considered that Cu2+ at low concentration in the bath solution could promote Ito and Idr while at high concentration could inhibit them, and change of amplitude was different with different membrane voltage. Conclusion was drawn: Cu2+ may be involved in the pathophysiologic mechanism of diseases with neuropathological components.