溶血磷脂酸对豚鼠心室乳头肌动作电位及收缩力的影响

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

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、10.0μmol.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10.0μmol.L-1组,灌流洗脱后,加入四乙基铵(TEA)20 mmol.L-1+LPA10.0μmol.L-1,观察TEA对LPA作用的影响。结果:LPA1.0和10.0μmol.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10.0μmol.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LPA10.0μmol.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。

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^-1 groups, 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 10.0μmol·L^-1 group were perfused with TEA 20 mmol·L^-1 ＋ LPA 10μmol·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 10.0μmol·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 APDs0 compared with LPA 10 μmol·L^-1 group （P〈0.05）. Oonclusion LPA could increase APA, prolong action potential duration and increase contraction force.