【摘要】 在急性分离的大鼠背根神经节 (dorsalrootganglion ,DRG)细胞上 ,应用全细胞膜片箝技术观察了预加催产素 (oxytocin ,OT)对GABA激活电流的调制作用。结果如下 :(1)大多数细胞 (4 8/ 5 2 ,90 5 % )对GABA敏感。(2 )OT可引起 5 1 3% (2 0 / 39)的受检细胞出现外向膜电流 ;43 6 % (17/ 39)无明显膜反应 ;5 1% (2 / 39)出现内向膜电流。 (3)预加OT (10 -12 ～ 10 -9mol/L) 30～ 90s后 ,大部分GABA激活电流增加 (33/ 39,84 6 % ) ;少数无明显反应(4 / 39,10 3% )或略有抑制 (2 / 39,5 1% )。GABA (10 -4 mol/L)增强作用为浓度依赖性的 ,在OT浓度为 10 -12 、10 -11、10 -10 、10 -9mol/L时 ,GABA激活电流的增强分别为 :2 4 1± 7 6 % (n =6 ) ,33 4± 6 9% (n =9) ,40 2±6 5 % (n =13) ,6 7 2± 14 8% (n =5 )。当OT浓度升高 (10 -8及 10 -7mol/L)时 ,GABA激活电流不但不增高 ,反而被抑制。 (4 )预加OT后 ,GABA激活电流量 效曲线的Kd值降低 ,最大反应浓度增加。(5 )预加OT和未预加OT的电流 电压曲线显示 ,其翻转电位均在 0mV左右。以上结果提示 :OT受体激活后可能通过相应的胞内转导机制增强GABA激活电流 ,从而在初级感觉神经元水平加强GABA的突触前抑制作用而减弱感觉信息的传递更多还原

【Abstract】 Experiments were performed on freshly isolated dorsal root ganglion (DRG) neurons of rat. GABA A activated currents were recorded using the whole cell patch clamp technique. The majority of the neurons (48/52, 90 5%) were sensitive to GABA (10 -6 ～10 -3 mol/L). Application of oxytocin (OT) induced outward membrane responses in 51 3% (20/39) of the neurons, no apparent responses in 43 6% (17/39) and inward responses in 5 1% (2/39). 10 -12 , 10 -11 , 10 -10 and 10 -9 mol/L OT increased 10 -4 mol/L GABA activated currents to 24 1±7 6%( n =6), 33 4±6 9%( n =9), 40 2±6 5%( n =13) and 67 2±14 8%( n =5), respectively. After preapplication of OT, the Kd value for GABA A activated currents decreased, while the response obtained at the maximum concentration increased. The results suggest that the enhancement of GABA activated currents by OT may suppress primary sensory transmission by potentiating pre synaptic inhibition of GABA. [WT5HZ]更多还原