Effects of calmodulin antagonist (W-7) on phorbol ester (PMA)-induced contractile response in isolated rat aorta.
The aim of this study was to investigate effects of calmodulin antagonist (W-7) on the contractile response of the rat aorta induced by activation of protein kinase C (PKC) by phorbol ester. Phorbol 12-myristate 13-acetate (PMA) produced biphasic contraction i.e., a sustained contraction (initial contraction) and 17.9 +/- 1.7 min later, this progressively developed contraction was changed to a delayed contraction superimposed on the initial contraction. The delayed contraction was completely inhibited by treatment with nicardipine. The onset of the delayed contraction was significantly delayed by treatment with W-7, whereas same concentration of W-7 showed a weak relaxant effect (10%) on the PMA-induced maximal contraction of aorta. Higher concentration of W-7 strongly inhibited PMA-induced sustained contraction. These results suggest that PMA-induced biphasic contractile response may be regulated by calmodulin.
Suenaga
H
H
Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan.
Kasuya
Y
Y
Kamata
K
K
D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology*; D002147:Calmodulin / Q000037:antagonists & inhibitors* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013449:Sulfonamides / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D002147:Calmodulin; D013449:Sulfonamides; D014665:Vasodilator Agents; C017967:W 7; D013755:Tetradecanoylphorbol Acetate