GATING KINETICS OF SINGLE POTASSIUM CHANNEL OF CULTURED RAT CEREBRAL NEURON
大鼠大脑皮层神经元单离子钾通道门控动力学

Single potassium channel current of cultured rat cerebral neuron were recorded with cell-attached and inside-out patch clamp. The mixed kinetic parameters and the transition rates of aggregative conformation states were identified by residual error and nonlinear least square method. The kinetic characteristics of cell-attached patch on cultured cerebral neuron of new-born rat was different from that of inside-out patch at holding potential-40 mV with symmetric potassium solution in bath and pipette. The open time probability distribution function obeyed one state distribution and the mean open-time in cell-attached mode was 2.53 ms while in inside-out mode was 2.04 ms. The closed-time probability distribution function obeyed three states distribution and the mean closed-time was 3.36 ms in cell-attached mode but was 7.58 ms in inside-out mode. The transition rates of the four states were identified by nonlinear least square method. The channel mainly sojourned at the first and the second closed state in cell-attached mode, but mainly sojourned at the first closed state in inside-out mode duriog closed period.