[Relation of effects of matrine on rat vasa deferens to activation of calcium channels].
Effective mechanisms of matrine (Mat) in contraction were observed in isolated rat vasa deferens. Mat caused a strong concentration-dependent contraction of vasa deferens, and this contraction was competitively inhibited by prazosin (Pra, 10 mumol.L-1) and nifedipine (Nif, 50 nmol.L-1), with depression of maximal responses. Their pA2 value was 5.1 and 9.29, respectively. The contraction was also inhibited by verapamil (Ver, 1 mumol.L-1) with depression of maximal responses; but this antagonism was noncompetitive. Its pD2 value was 6.07. Mat promoted CaCl2-induced contraction of vas deferens. The effect of Mat was enhanced in proportion to increase in concentrations of CaCl2. Mat markedly strengthened KCl-induced contraction of vas deferens. The results suggest that one of the mechanisms of the contractive effects of Mat within a certain range of concentrations was related to the activation of the calcium channel.
Department of Pharmacology, Inner Mongolia Medical College, Huhehaote, China.
G L
GL
Wang
S S
SS
Zhang
Z H
ZH
Li
S F
SF
Liu
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011807:Quinolizines; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D014649:Vas Deferens; D014700:Verapamil / Q000494:pharmacology; D000093842:Matrines
D000470:Alkaloids; D002120:Calcium Channel Agonists; D011807:Quinolizines; D014700:Verapamil; D009543:Nifedipine; D011224:Prazosin; D000093842:Matrines