Mechanisms Involved in the Vasodilator Effect of Curine in Rat Resistance Arteries

Abstract

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 μM; IC₅₀ = 4.8 ± 1.3 μM and 4.8 ± 1.5 μM, respectively) and KCl (80 mM; IC₅₀ = 6.0 ± 1.3 μM and 13.0 ± 5.6 μM, respectively). Curine also inhibited (IC₅₀ = 4.6 ± 0.9 μM) the concentration-response curves induced by noradrenaline. Contractions dependent on calcium-influx elicited by KCl (80 mM) and noradrenaline (10 μM) were inhibited by curine (10 μM). Finally, contractions induced by noradrenaline (10 μM), in calcium-free medium, were strongly inhibited by curine (10 μM). 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.

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