CAJ | 학술논문

应用全细胞膜片钳记录大鼠新鲜分离背根神经节(DRG)神经元GABA-激活电流,观察咖啡因对GABA-激活电流(IGABA)的调制作用.结果显示:大部分受检细胞(97.4%,113/116) 对外加GABA敏感.1-1000 μmol/L GABA引起一剂量依赖性、有明显去敏感作用的内向电流.预加咖啡因(0.01-100 μmol/L)30 s后再加GABA能明显抑制GABA(100 μmol/L )激活电流的幅值.预加咖啡因后GABA量效曲线明显下移;GABA-激活电流的最大值较之对照下降约57%;而Kd值(30 μmol/L)几乎不变.该结果提示此种抑制为非竞争性的.预加氨茶碱(theophylline)亦可明显抑制GABA激活电流,同一浓度(10 μmol/L)下氨茶碱的抑制作用较咖啡因的抑制作用强.预加安定(diazepam, 1 μmol/L)对GABA(10 μmol/L )激活电流有增强作用,而预加咖啡因(10 μmol/L )有拮抗安定增强IGABA的作用.胞内透析H-8后,几乎可以完全消除咖啡因对IGABA的抑制作用.本结果表明咖啡因在初级传入末稍可能产生对抗突触前抑制的效应.
응용전세포막편겸기록대서신선분리배근신경절(DRG)신경원GABA-격활전류,관찰가배인대GABA-격활전류(IGABA)적조제작용.결과현시:대부분수검세포(97.4%,113/116) 대외가GABA민감.1-1000 μmol/L GABA인기일제량의뢰성、유명현거민감작용적내향전류.예가가배인(0.01-100 μmol/L)30 s후재가GABA능명현억제GABA(100 μmol/L )격활전류적폭치.예가가배인후GABA량효곡선명현하이;GABA-격활전류적최대치교지대조하강약57%;이Kd치(30 μmol/L)궤호불변.해결과제시차충억제위비경쟁성적.예가안다감(theophylline)역가명현억제GABA격활전류,동일농도(10 μmol/L)하안다감적억제작용교가배인적억제작용강.예가안정(diazepam, 1 μmol/L)대GABA(10 μmol/L )격활전류유증강작용,이예가가배인(10 μmol/L )유길항안정증강IGABA적작용.포내투석H-8후,궤호가이완전소제가배인대IGABA적억제작용.본결과표명가배인재초급전입말초가능산생대항돌촉전억제적효응.
Whole-cell patch clamp technique was performed on acutely isolated rat dorsal root ganglion (DRG) neurons to investigate the modulatory effect of caffeine on γ-aminobutyric acid (GABA)-activated currents (IGABA). The results showed that the majority of the neurons examined (97.4%, 113/116) were sensitive to GABA. 1-1000 μmol/L GABA activated a concentration-dependent inward current which manifested obvious desensitization. After the neurons were treated with caffeine (0.01-100 μmol/L) prior to the application of GABA (100 μmol/L) for 30 s, GABA-activated membrane currents were obviously inhibited. Caffeine shifted the GABA dose-response curve downward and decreased the maximum response to 57% without changing Kd value. These results indicate that the inhibitory effect is non-competitive. Theophylline showed a similar and stronger inhibitory effect on IGABA. The pretreatment with caffeine (10 μmol/L) inhibited IGABA, which was potentized by diazepam (1 μmol/L). Intracellular application of H-8 almost completely abolished the inhibitory effect of caffeine on IGABA. The present results suggest that caffeine may be able to antagonize the effect of presynaptic inhibition of GABA in primary afferent.