6533b858fe1ef96bd12b5af5
RESEARCH PRODUCT
Tetrandrine and Isotetrandrine, Two Bisbenzyltetrahydroisoquinoline Alkaloids from Menispermaceae, with Rat Uterine Smooth Muscle Relaxant Activity
Pilar D'oconElsa AnselmiM. Amparo BlázquezAlmudena Bermejosubject
StereochemistryPharmaceutical ScienceIn Vitro TechniquesPharmacologyOxytocinBenzylisoquinolinesUterine contractionUterine Contractionchemistry.chemical_compoundAlkaloidsmedicineAnimalsPharmacologyDose-Response Relationship Drugbusiness.industryAlkaloidCalcium channelAnti-Inflammatory Agents Non-SteroidalUterusMuscle SmoothRats Inbred StrainsStereoisomerismBiological activityAcetylcholineRatsTetrandrineOxytocinchemistryDepression ChemicalFemalemedicine.symptombusinessAcetylcholinemedicine.drugMuscle contractiondescription
Abstract The effects of two bisbenzyltetrahydroisoquinoline alkaloids, 1S, 1′S tetrandrine and its isomer 1R, 1′S isotetrandrine, were investigated in rat isolated uterus in order to identify the mechanism of relaxant action and to study the influence of the absolute configuration on the activity of these alkaloids. Both inhibited the uterine contraction induced by high K+, acetylcholine and oxytocin. In Ca2+-free medium, isotetrandrine relaxed the sustained contraction induced by oxytocin but tetrandrine did not. The relaxant effects of the alkaloids may be due to blockade of calcium influx through specific channels. Tetrandrine and isotetrandrine modify the calcium channel in a nonreversible manner whilst only isotetrandrine acts intracellularly. Tetrandrine shows a more specific relaxant activity as a calcium entry blocker.
year | journal | country | edition | language |
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1992-07-01 | Journal of Pharmacy and Pharmacology |