溶血磷脂酸对豚鼠心室乳头肌动作电位及收缩力的影响

目的：观察溶血磷脂酸（LPA）对离体豚鼠心室乳头肌动作电位及收缩力的影响。方法：健康成年豚鼠18只，随机分LPA 0.1、1.0、10.0 μmol?L^-1组，每组6只，采用给药前后自身对照的方法观察LPA对豚鼠乳头肌的作用。对10.0 μmol?L^-1组，灌流洗脱后，加入四乙基铵(TEA)20 mmol?L^-1+ LPA 10 .0 μmol?L^-1，观察TEA对LPA作用的影响。结果：LPA1.0和10.0 μmol?L^-1组乳头肌收缩幅度由给药前的100%增加到(122.6±7.9)% 和(139.48±8.2)%（P<0.05或P<0.01）。LPA 0.1 、1.0和10.0 μmol?L^-1组心室肌动作电位的幅度（APA）由给药前的（106.79±11.80 ）、（96.86±9.81）和（100.22±7.55）mV升高到（113.49±12.66）、（112.54±10.07）和（118.91±10.62）mV（P<0.05或P<0.01）；动作电位50%时程（APD₅₀）和动作电位90%时程(APD₉₀)均较给药前延长（ P<0.05）。20 mmol?L^-1的TEA 可使LPA 10.0 μmol?L^-1对APD₅₀的作用降低（P<0.05）。结论：LPA可增加豚鼠心脏乳头肌动作电位幅值，延长动作电位时程，增加心室肌收缩力。

Effects of lysophosphatidic acid on action potential and contraction force in guinea pig papillary muscles

Objective To observe the effects of lysophosphatidic acid(LPA)on the action potential and contraction force in guinea pig papillary muscles.Methods Eighteen healthy adult guinea-pigs were randomly divided into LPA 0.1,1.0,10.0 μmol·L-1groups,with six guinea pigs in every group compared with themselves before administration to observe the effects of LPA on the papillary muscles.The pigs in 10.0 μmol·L-1 group were perfused with TEA 20 mmol·L-1+ LPA 10 μmol·L-1 after desorption.Results LPA 1.0,10.0 μmol·L-1 could increase contraction force in guinea pigs compared with themselves before administration from 100% to(122.6±7.9)% and(139.48±8.2)%(P<0.05,P<0.01).The LPA at different doses(0.1,1.0,and 10.0 μmol·L-1) could increase the action potential amplitude(APA) compared with themselves before administration from(106.79±11.80),(96.86±9.81),(100.22±7.55)mV to(113.49±12.66),(112.54±10.07),(118.91±10.62)mV(P<0.05 or P<0.01);the action potential durations measured at the 50% repolarization levels and the 90% repolarization levels were prolonged compared with before administation(all P<0.05).TEA(20 mmol·L-1) shortened the APD50 compared with LPA 10 μmol·L-1 group(P<0.05).Conclusion LPA could increase APA,prolong action potential duration and increase contraction force.