二氧化硫衍生物对大鼠背根神经元瞬间外向钾电流和延迟整流钾电流的影响

运用全细胞膜片钳技术研究二氧化硫衍生物对大鼠背根神经元瞬间外向钾电流(IA和ID)和延迟整流钾电流(IK)的影响。结果发现二氧化硫衍生物剂量依赖性地增大钾通道的电导,电压依赖性地增大钾电流的幅度,且这种增大作用部分可逆。二氧化硫非常显著地使延迟整流钾电流的激活过程向超极化方向移动,使瞬间外向钾电流的失活过程向去极化方向移动。10μmol/L二氧化硫衍生物作用前后,延迟整流钾电流的半数激活电压分别是(20.3±2.1)mV和(15.0±1.5)mV;IA和ID的半数失活电压分别朝去极化方向移动了6mV和7.4mV。这些结果表明二氧化硫改变了钾通道的特性,改变了神经元的兴奋性。

Enhancement of potassium currents in rat dorsal root ganglion neurons by sulfur dioxide derivatives

This study addressed the effect of sulfur dioxide (SO₂) derivatives on transient outward potassium currents (I_A and I_D) and delayed rectifier current (I_K) in somatic membrane of freshly isolated rat dorsal root ganglion neurons using the whole cell configuration of patch-clamp technique. SO₂ derivatives reversibly increased the amplitudes of potassium currents in a concentration-dependent and voltage-dependent. SO₂ derivatives significantly shifted the activation of delayed rectifier potassium current in the hyperpolarizing direction and shifted the inactivation curve of transient outward potassium currents in the depolarizing direction. Parameters for the fit of a Boltzmann equation to mean values for delayed rectifier current activation were V_1/2=20.3±2.1 mV before and 15.0±1.5 mV after application 10 μM SO₂ derivatives. The half inactivation of I_A was shifted 6 mV and I_D 7.4 mV after application 10 μM SO₂ derivatives. These results indicated that SO₂ derivatives increased the amplitudes of potassium currents and changed the properties of potassium channels.