乙酰胆碱对豚鼠左心室流出道电生理效应的研究

Effects of acetylcholine on electrophysiological features of guinea-pig left ventricular outflow tract

目的探讨乙酰胆碱(acetylcholine,ACh)和阿托品(atropine)对豚鼠左心室流出道自律细胞电生理特性的影响。方法用标准玻璃微电极细胞内记录技术,观测ACh和阿托品对豚鼠左心室流出道自发慢反应电位的影响。观测指标:最大舒张电位(MDP)、动作电位幅度(APA)、0期最大除极速度(Vmax)、4期自动除极速度(VDD)、复极50%(APD50)和90%(APD90)时间以及自发放电频率(RPF)。结果1μmol/LACh可使左心室流出道自发慢反应电位Vmax减慢(P<0.05),其余指标差异无显著性;10μmol/LACh灌流标本后,自发慢反应电位Vmax(P<0.01)和VDD(P<0.05)显著减慢;100μmol/LACh可使RPF和VDD显著减慢(P<0.05),APA显著降低(P<0.01),Vmax明显减慢(P<0.01),APD50显著缩短(P<0.05);100μmol/L阿托品可拮抗100μmol/LACh所致的自发慢反应电位APD50的缩短(P<0.05)。结论ACh可降低左心室流出道组织的自律性,阿托品可拮抗ACh对APD50的缩短效应。

[Objective] To explore the effects of acetylcholine（ACh ） and atropine on spontaneous slow action potentials （Aps） of guinea-pig left ventricular outflow tract cells. [Methods] By using standard intracellular microelectrode technique to record APs, ACh and atropine were used to investigate the electrophysiological features of left ventricular outflow tract pacemaker cells. Electrophysiological parameters examined were： maximal diastolic potential （MDP）, amplitude of action potential （APA）, maximal rate of depolarization（Vmax）, velocity of diastolic depolarization （VDD）, rate of pacemaker firing （RPF）, and 50% and 90% of duration of action potential （APD50 and APD90）. [Results] During perfusion with 1μmol/L ACh Vmax slowed down notably （P 〈0.05）; Perfusion with 10μmol/L ACh resulted in a significant decrease in VDD （P 〈0.05） and Vmax （P 〈0.01）; Application of 100 μmol/L ACh resulted in a noteble decrease in VDD and RPF （P 〈0.05） , a significant decrease in Vmax and APA （P 〈0.01）, and a marked shortening in APD50 （P 〈0.05）; 100μmol/L atroPine antagonized the effects of ACh（100 μmol/L） on APD50 （P 〈 0.05） significantly. [Conclusion] ACh could slowed down the autorhythmicity of left ventricular outflow tract and the effects varies from different doses of ACh. Atropine could antagonite the effect of ACh on APD50 （P 〈0.05）.