氯胺酮对哮喘大鼠气管平滑肌细胞ATP敏感钾电流的影响

Effect of ketamine on ATP-sensitive K^+ currents in airway smooth muscle cells of asthmatic rat

目的 研究氯胺酮对哮喘大鼠单一气管平滑肌细胞ATP敏感钾电流 (IKATP)的作用。方法 急性分离哮喘大鼠气管 ,利用膜片钳制技术全细胞记录法观察氯胺酮对哮喘大鼠单一气管平滑肌细胞IKATP的作用。结果 氯胺酮开放气管平滑肌细胞ATP敏感钾通道 (KATP通道 ) ,且具有剂量依赖关系。指令电位在 + 50mV时 ,4种浓度氯胺酮 (1×10 - 7,1× 10 - 6 ,1× 10 - 5 ,1× 10 - 4mol·L- 1)可使IKATP 由53 72± 15 60 pA/pF增加到给药后的 63 86± 19 3 3 pA/pF(n =8,P <0 0 5) ,69 98± 18 44pA/pF(P <0 0 1) ,75 64±19 64pA/ pF (P <0 0 1)和 78 3 7± 19 40pA/ pF (P <0 0 1)。其开放率分别为 118 73 %± 2 2 0 1% (P <0 0 5) ,13 5 18%± 2 7 79% (P <0 0 5) ,14 7 0 7%± 3 3 2 5% (P <0 0 5)和 153 62 %± 3 7 59% (P <0 0 5)。其它指令电位下的IKATP改变也符合此趋势。结论 氯胺酮剂量依赖性的开放哮喘大鼠单一气管平滑肌细胞ATP敏感钾通道 。

AIM To investigate the effect of ke tamine on ATP-sensitive K + currents (I K ATP ) in single airway smooth muscle (ASM) cells of asthmatic rat. METHODS Single ASM cells of asthmatic rat were isolated with enzymatic dissociation technique. Effect of ketamine on I K ATP in single ASM cells was studied using the whole-cell configu ration of patch clamp technique. RESULTS Ketamine opened the ATP -sensitive K + channel (K ATP channel) in a dose-dependent manner. When the concentrations of ketamine were 1×10 -7 ,1×10 -6 ,1×10 -5 and 1×10 -4 mol·L -1 , the amplitude values of I K ATP were increased to 63 86±19 33 pA/pF(n=8,P<0 05),69 98±18 44 pA/pF(P<0 01),75 64±19 64 pA/pF(P<0 01)and 78 37±19 40 pA/p F(P<0 01), from 53 72±15 60 pA/pF of control, respectively. The open r ates were 118 73%±22 01%(P<0 05),135 18%±27 79%(P<0 05),14 7 07%±33 25%(P<0 05) and 153 62%±37 59%(P<0 05)respectively. The changes of I K ATP under other command potentials were consis tent with this. CONCLUSION Ketamine opens ATP-sensitive K + cha nnel in single airway smooth muscle cells of asthmatic rat in a dose-dependent manner.