牛磺酸对蟾蜍椎旁交感神经细胞作用的离子机制研究

Effects of Taurine on Paravertebral Sympathetic Ganglion of the Toad and the Mechanisms of Its Ions

目的 :观察蟾蜍椎旁交感神经节的牛磺酸含量以及牛磺酸所致蟾蜍椎旁交感神经节细胞膜电位变化和它的离子机制。方法 :采用高压液相层析测定蟾蜍椎旁交感神经节的牛磺酸含量和应用细胞外微电极技术记录离体灌流的蟾蜍椎旁交感神经节细胞膜电位。结果 :蟾蜍椎旁交感神经节的牛磺酸含量为 (1.40± 0 .36 ) μg/mg(蟾蜍神经节湿重 )。外源性牛磺酸 (10 0mmol/L)可引起超极化化反应 ,使其幅值减小 (6 2 .14± 2 5 .48) % (n =10 ,P <0 .0 1)。无钠液灌流可加强牛磺酸的去极化反应 ,且去极化之后伴随超极化反应 ,使其去极化幅值增大 (16 0 .2 6±36 .18) % (n =8,P <0 .0 1) ,超极化的幅值为 (4.6 3± 17.92 )mv(n =8)。用无钙液灌流对牛磺酸的去极化有抑制作用 ,使其幅值减小 (46 .42± 32 .16 ) % (n =8,P <0 .0 1) ,对牛磺酸超极化反应无明显的影响。结论 :蟾蜍椎旁交感神经节含有牛磺酸。牛磺酸导致蟾蜍椎旁交感神经节细胞出现超极化反应 ,去极化反应和超极化后伴随去极化的双相反应。Cl-是介导超极化反应的主要电荷载体 ,而Ca2 + 则是介导去极化反应的主要电荷载体。

Objective:To observe the content of taurine as well as the change in surface potentials induced by taurine and the mechanisms of its ions in the isolated paravertebral sympathetic ganglia of the toad.Methods:The content of taurine was measured by high performance liquid chromatography and the surface potentials were recorded with the extracellular microelectrode technique in the isolated paravertebral sympathetic ganglion(PSG)of the toad.Results:The content of taurine(TAU) in the toad paravertebral sympathetic ganglia was(1.40±0.36) μg/mg PSG wet weight.Exogenous TAU(100 mm/L)induced a hyperpolarization response(n=40), a depolarization response( n =27) and a biphasic response which appeared as a hyperpolarization followed by a depolarization( n =3).Low Cl - perfusate depressed the TAU induced hyperpolarization response by (62.14±25.48)%( n =10, P &lt;0.01). Na + ion free perfusate augmented TAU induced depolarization by( 160.26 ±36.18)%( n =8, P &lt;0.01)and depolarization was followed by hyperpolarization with a range of (4.63±17.92)mv( n =8). Ca 2+ free perfusate depressed depolarization, induced by TAU, to (46.42±32.16)%( n =8, P &lt;0.01) and had no significant effects on the hyperpolarization induced by TAU.Conclusion:The results show that there is taurine in the paravertebral sympathetic ganglia of the toad.There are the TAU induced hyperpolarization response,depolarization response,and biphasic response that appeared as a hyperpolarization followed by a depolarization in the isolated paravertebral sympathetic ganglia of the toad. It is probable that Cl anions are the main carriers for the hyperpolarization,Ca 2+ ions are the main carriers for the depolarization shown in the present study.