[Suppression effect of ketamine on transient outward potassium currents in rathippocampal neurons].

OBJECTIVE: To investigate the effect of ketamine on the transient outward potassium currents [IA] using whole-cell patch clamp technique. METHODS: Pyramidal neurons were enzymatically isolated from Wistar rat hippocampus. The effect of ketamine on the [IA] was assessed using whole-cell patch clamp technique. Different concentrations of ketamine were added and potassium currents were measured. RESULTS: [IA] was inhibited by ketamine in a concentration-dependent manner. 10 micromol/L ketamine had no effect on [IA]. The four concentrations of ketamine (30, 100, 300, 1000 micromol/L) reduced peak [IA] currents by (11+/-2)%, (22+/-3)%, (45+/-5)%, (53+/-5)% respectively, with a mean IC50 of (130+/-24) micromol/L and Hill coefficient of 1.19+/-0.56. The V1/2 of activation curve was shifted from (-8.70+/-0.13) mV to (-11.2+/-2.10) mV (n=8, P<0.05). The V1/2 of inactivation curve was shifted from (-75.53+/-7.98) mV to (-91.94+/-11.85) mV (n=8, P<0.05). CONCLUSION: Ketamine produces significant inhibition of potassium currents in the central neurons, which may least partly explain at the action of ketamine.