论文部分内容阅读
运用细胞内记录和全细胞膜片钳技术 ,在 7～ 16d大鼠带三叉神经残根的 4 0 0 μm厚脑桥切片上进行研究。细胞内电流钳记录显示三叉神经主核灌流甘丙肽引发两种膜电位变化 :54.2 %细胞超极化 (3.2±1.2 )mV ;35.4 %细胞去极化 (2 .9± 1.3)mV ,两者均伴有兴奋性突触后电位抑制和膜电阻减小。电压钳实验显示甘丙肽也引致两种膜电流变化 :57.9%细胞出现外向性电流 (11.6± 6 .1)pA ,该电流可被四乙基胺所抑制 ,其反转电位为 (- 77.1± 5.3)mV ;2 7.3%细胞出现内向性电流 (10 .9± 5.9)pA ,该电流可被细胞外低钠所抑制而被细胞外高钾所增强 ,其反转电位为 (- 2 9.2± 4 .3)mV。两电流均可被甘丙肽激动剂M16所模拟 ,为甘丙肽阻断剂M35和M4 0所阻抑。上述结果提示 ,甘丙肽在突触后膜引发两种不同的膜电活动 :钾离子外流引发超极化和外向性电流 ;钠离子内流和钾离子外流引发去极化和内向性电流 ,两种反应均能抑制三叉神经主核神经元的突触传递。
Intracellular recordings and whole-cell patch-clamp techniques were performed on 400-μm-thick pons containing 7-to 16-day rats with trigeminal nerve root residues. Intracellular current clamp recordings showed that there were two changes in membrane potentials induced by galanin in the trigeminal main nucleus: 54.2% cells hyperpolarized (3.2 ± 1.2) mV; 35.4% cells depolarized (2.9 ± 1.3) mV, two All were accompanied by excitatory postsynaptic potential inhibition and membrane resistance reduction. Voltage clamp experiments also showed that galanin also caused two changes in membrane current: 57.9% of cells showed an outward current (11.6 ± 6 .1) pA, which was inhibited by tetraethylamine with a reversal potential of -77.1 ± 5.3) mV; 2 7.3% cells showed an inward current of (10.9 ± 5.9) pA, which was inhibited by extracellular low sodium and increased by extracellular potassium with a reversal potential of -2.2 × ± 4 .3) mV. Both currents were mimicked by the galanin agonist M16 and inhibited by the galanin blockers M35 and M4o. The above results suggest that galanin induces two different membrane electrical activities in the postsynaptic membrane: potassium ion outflow induces hyperpolarization and outward currents; sodium ion influx and potassium outflow induce depolarization and inward currents, Both responses inhibited synaptic transmission in the primary trigeminal neurons.