Modulation of KCNQ2 and KCNQ3 potassium channels by extracellular pH / 中国药理学通报

ABSTRACT

Aim To study the modulation of KCNQ2/3 potassium cha nn els by extracellular pH.Methods In vitro transcription was used to synthesize cRNA of KCNQ2/3 potassium channels.The cRNA was injected into Xenopus oocytes to express the KCNQ2/3 channel.The modulation of KCNQ2/3 potass ium channels by extracellular pH was studied by two electrodes voltage clamp tec hniques.Results KCNQ2/3 currents were inhibited and current-vo ltage relationship of activation were shifted to the right with decreased extrac ellular pH. pH modulation of KCNQ2/3 currents was voltage dependent,with a more pronounced effect at more negative potentials above the activation threshold (-60 mV). Extracelluar pH also decreased activation and deactivation kinetics of KCNQ2/3 currents.Conclusion KCNQ2/3 channels, known to contr ibute to neuronal excitability, were modulated by extracelluar pH. The profound effects of the extracelluar pH exerted on KCNQ2/3 channel may play an important role during physiology neuronal activity and pathological events such a s epileptic seizures, cerebral ischemia and shock etc.