Effect of 2,3-butanedione monoxime on smooth-muscle contraction of guinea-pig portal vein.
Effects of 2,3-butanedione-2-monoxime (BDM) on the contraction of intact and skinned smooth muscles from guinea-pig portal vein were examined. In intact preparations loaded with fura-2, 5-10 mM BDM markedly suppressed Ca2+ transients and force developments induced by 154 mM potassium and by phenylephrine (0.1 mM). On the other hand, in Ca(2+)-free depolarizing solution, BDM did not suppress phenylephrine (0.1 mM)-induced Ca2+ transient and force development. In skinned preparations obtained with Staphylococcus aureus alpha-toxin treatment, BDM did not markedly affect active force development. The above results indicate that BDM suppresses contraction of the portal vein mainly by the inhibition of voltage-dependent cytosolic Ca2+ transients. An additional result suggests that BDM suppresses the force-enhancing effect of alpha 1-adrenergic agents on the contractile elements.
Watanabe
M
M
Department of Physiology, Jikei University School of Medicine, Tokyo, Japan.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D003931:Diacetyl / Q000031:analogs & derivatives* / Q000494:pharmacology; D004594:Electrophysiology; D005260:Female; D016257:Fura-2; D006168:Guinea Pigs; D006652:Histological Techniques; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010656:Phenylephrine / Q000494:pharmacology; D011169:Portal Vein / Q000187:drug effects* / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*
C004717:diacetylmonoxime; D010656:Phenylephrine; D003931:Diacetyl; D011188:Potassium; D002118:Calcium; D016257:Fura-2