前胡丙素对豚鼠心房和兔主动脉条的钙拮抗作用

Calcium-antagonistic effects of praeruptorin C on isolated guinea pig atria and rabbit aorta

前胡丙素(Pra—C)非竞争性抑制CaCl_2和高钾除极化所致兔主动脉条的收缩,pD’_2值分别为4.9和5.0;抑制5—HT诱导的依外钙性收缩,但不影响依内钙性收缩及NE诱导的收缩;Pra—C5～50μmol/L浓度依赖性地抑制豚鼠左房收缩力和阶梯现象;Pra—C抑制血管与心脏的IC_(50)之比为1:8。结果提示Pra—C对血管和心脏的抑制作用可能与拮抗Ca^(2+)有关,且主要影响经PDCs的外钙内流。

In the isolated rabbit aorta,praerup-torin C(Pra-C)inhibited the contractions induced by calcium and potassium depolarization and shifted the concentration-response curve nonparallelly to right.pD2 value is 4.9 and 5.0 respectively.It did not possess relevant antagonistic effects against norepinephrine-induced contractions and significantly inhibited the sustained tonic but not the initial phasic component of the contractions induced by serotonin,showing itslittle effect on the intracellular calcium release.At the concentration of 5-50μmol/L,Pra-C inhibited the contractility and staircase phenomenon of the left atria in a dose-dependant manner but seldom affected post-rest potentiation.These results indicated that Pra-C had calcium-antagonistic effects on the isolated rabbit aorta and guinea pig atria and mainly blocked calcium influx through PDCs.