脊髓中PK－C激动剂佛波醇酯和抑制剂他莫昔芬引起的心血管效应

THE CARDIOVASCULAR REACTIONS MEDIATEED BY TPA AND TAMOXIFEN IN SPINAL CORD OF CONSCIOUS RATS

给清醒大鼠脊髓蛛网膜下腔注射（ｉｔｈ）不同剂量的ＰＫＣ激动剂佛波醇酯（ＴＰＡ）后，平均动脉压（ｍＡＢＰ）呈明显剂量效应关系的上升，但心率（ＨＲ）无明显改变。不同剂量的ＰＫＣ抑制剂他莫昔芬（ｔａｍｏｘｉｆｅｎ）则使ｍＡＢＰ下降，亦有量效关系。给大鼠ｉｔｈ不同剂量二丁酰环磷酸腺苷（ＤＢｃＡＭＰ）也引起加压效应，并使ＨＲ减慢。在有效剂量（２．５μｇ·μｌ－１）的ＤＢｃＡＭＰ作用下，ＴＰＡ的加压效应可得到明显的增强。

Intrathecal administration (ith)of phorbol 12-myristate(TPA),an activator of protein kinase C,(31.24,26.5, 125 and250ng/10μg)to conscious rats proeduced a marked dose-denpendent pressor effect without significanchange in heart rate (HR).Intrathecal administration of tamoxifen (3.125,6.5 andl00μg/μl), one of the inhibitors of protein kinase C, produced amarked dose-dependent hypotensive effect.Intrathecal injection of exogenous DBcAMP(12.5,25, 50and 100μh/10μl)also incresed the mean arterial blood pressure(mABP)and markedly lowered HR.It was further observed that, based on the effect of DBcAMP(25μg/10μl),the pressor effect of fourdoses of TPA can be augmented.The results indicate that TPAin spinal cord may exert hypertensive effect via activation of PKCand tamoxifen may exert a hypotensive effect via inhibition of PKC,in addition, the pressor effect ofTPA could be augmented by preadministration of DBcAMP.