Yang Yue, Si Jun-Qiang, Fan Chao, Ma Ke-Tao, Cheng Hong-Jv, Li Li
The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihen University Medical College, Shihezi 832002, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2013 May;29(3):263-6.
To investigate the effects of ropivacaine on Gamma-aminobutyric acid(GABA)-activated currents in dorsal root ganglion (DRG) neurons in rats and discuss the analgesia mechanism of ropivacaine.
By means of using whole-cell patch-clamp technique, to investigate the modulatory effects of ropivacaine on GABA-activated currents (I(GABA)) in acutely isolated dorsal root ganglion neurons.
(1) In 48 out of 73DRG cells (65.7%, 48/73), to perfusion ropivacaine bromide (0.1 - 1 000 micromol/L) were sensitive. Which produce in 0 to 380 pA current. (2) The majority of the neurons examined (74.5%, 73/98) were sensitive to GABA. Concentration of 1 - 1 000 micromol/L GABA could activate a concentration-dependent inward current, which manifested obvious desensitization, and the inward currents could be blocked byGABA-receptor selective antagonist of bicuculline (100 micromol/L). (3) After the neurons were treated with ropivacaine (0.1 - 1000 micromol/L) prior to the application of GABA (100 micromol/L) 30 s, GABA currents were obviously increased. Ropivacaine could make dose-response curve of the GABA up, EC50 is 23.46 micromol/L. Ropivacaine shifted the GABA dose-response curve upward and increased the maximum response to the contrast about 153%.
The enhancement of ropivacaine to DRG neurons activation of GABA current, can lead to enhancement of pre-synaptic inhibition at the spinal cord level. This may be one of the reasons for the anesthetic effect and analgesia for ropivacaine in epidural anesthesia.
研究罗哌卡因对大鼠背根神经节（DRG）神经元γ-氨基丁酸（GABA）激活电流的影响，并探讨罗哌卡因的镇痛机制。
采用全细胞膜片钳技术，研究罗哌卡因对急性分离的背根神经节神经元GABA激活电流（I(GABA)）的调制作用。
（1）73个DRG细胞中有48个（65.7%，48/73）对灌注溴化罗哌卡因（0.1 - 1000 μmol/L）敏感，可产生0至380 pA的电流。（2）大多数被检测的神经元（74.5%，73/98）对GABA敏感，1 - 1000 μmol/L的GABA浓度可激活浓度依赖性内向电流，表现出明显的脱敏现象，且内向电流可被GABA受体选择性拮抗剂荷包牡丹碱（100 μmol/L）阻断。（3）在神经元用罗哌卡因（0.1 - 1000 μmol/L）处理30 s后再施加100 μmol/L的GABA，GABA电流明显增加。罗哌卡因可使GABA的剂量-反应曲线上升，半数有效浓度（EC50）为23.46 μmol/L。罗哌卡因使GABA剂量-反应曲线向上移位，最大反应增加约153%。
罗哌卡因增强DRG神经元GABA电流的激活，可导致脊髓水平突触前抑制增强。这可能是罗哌卡因在硬膜外麻醉中产生麻醉和镇痛作用的原因之一。
