[Effect of ketamine on high-voltage-activated calcium currents in rat hippocampal neurons].

ABSTRACT

OBJECTIVE: To investigate the effect of ketamine on the high-voltage-activated calcium currents (ICa(HVA)) in rat hippocampal neurons. METHODS: Neurons were cultured from Wistar rat hippocampus. ICa(HVA) was recorded using whole-cell patch clamp technique. After application with ketamine at different concentrations (10, 30, 100, 300, and 1000 µmol/L), the effect of ketamine on ICa(HVA) was evaluated. RESULTS: ICa(HVA) was inhibited by ketamine in a concentration-dependent manner. Ketamine at 10 µmol/L showed no effect on ICa(HVA). Four concentrations of ketamine (30, 100, 300,and 1000 µmol/L) reduced the peak ICa(HVA) currents by (17.5 ∓ 4.5)%, (25.5 ∓ 6.9)%, (38.5 ∓ 4.1)%, and (42.3 ∓ 4.6)% respectively,with a mean half maximal inhibitory concentration of 68.2 µmol/L and Hill coefficient of 0.47. The maximal activation membrane potential was shifted to (5.3 ∓ 0.8) from (5.4 ∓ 0.9). The half maximal activation membrane potential of inactivation curve was shifted from(-26.7 ∓ 3.9) mV to(-32.8 ∓ 4.2) mV. CONCLUSION: Ketamine can remarkably inhibit calcium currents in the central neurons,which may explain at least partly the action of ketamine on central nervous system.