Ca2(+)-dependence of endothelin-1 induced contraction of rat tail artery.
1. In rat tail artery, endothelin-1(ET-1) caused an increase in the cytosolic free Ca2+ level ([Ca2+]i) followed by a relatively sustained but not steady-state contraction in Ca2+ containing solution. 2. In the early phase of the contraction, the rate of increase in [Ca2+]i, was much faster than that in muscle tension. However, after the increases in [Ca2+]i and muscle tension reached at their peaks, there was a good correlation between the changes of the two parameters. 3. ET-1 could not induce an apparent contractile response in Ca2(+)-free medium, notwithstanding it evoked a [Ca2+]i transient in this medium. 4. The results indicate that ET-1 induce a contraction of rat tail artery which is almost fully dependent on the [Ca2+]i changes, and may inhibit the Ca2(+)-sensitivity of the contractile filaments in the early phase of the contraction.
Huang
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Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Takayanagi
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Kurata
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Hisayama
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D000818:Animals; D001158:Arteries / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D016232:Endothelins / Q000494:pharmacology*; D005260:Female; D016257:Fura-2 / Q000494:pharmacology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects; D013623:Tail / Q000098:blood supply
D016232:Endothelins; D002110:Caffeine; D002118:Calcium; D016257:Fura-2