Mechanisms involved in the vasodilator effect of curine in rat resistance arteries.
The vasodilator effect of curine was investigated in the rat small mesenteric arteries. In either endothelium-intact or endothelium-denuded mesenteric arteries, curine induced a concentration-dependent relaxation in rings pre-contracted with noradrenline (10 microM; IC 50 = 4.8 +/- 1.3 microM and 4.8 +/- 1.5 microM, respectively) and KCl (80 mM; IC 50 = 6.0 +/- 1.3 microM and 13.0 +/- 5.6 microM, respectively). Curine also inhibited (IC 50 = 4.6 +/- 0.9 microM) the concentration-response curves induced by noradrenaline. Contractions dependent on calcium-influx elicited by KCl (80 mM) and noradrenaline (10 microM) were inhibited by curine (10 microM). Finally, contractions induced by noradrenaline (10 microM), in calcium-free medium, were strongly inhibited by curine (10 microM). The above results suggest that the inhibition of influx of calcium ions through voltage-operated calcium channels and non-selective channels, and mobilization of intracellular calcium stores sensitive to noradrenaline are involved in the vasodilator effect of curine.
Dias
Celidarque S
CS
Barbosa-Filho
José M
JM
Lemos
Virgínia S
VS
Côrtes
Steyner F
SF
D000818:Animals; D002118:Calcium / Q000378:metabolism; D003374:Coumarins / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D020128:Inhibitory Concentration 50; D008297:Male; D029583:Menispermaceae; D008638:Mesenteric Arteries / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D011189:Potassium Chloride; D051381:Rats; D017208:Rats, Wistar; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
C470479:5-hydroxyramulosin; D003374:Coumarins; D010936:Plant Extracts; D014665:Vasodilator Agents; D011189:Potassium Chloride; D002118:Calcium; D009638:Norepinephrine