Jabuticaba-Induced Endothelium-Independent Vasodilating Effect on Isolated Arteries

BACKGROUND: Despite the important biological effects of jabuticaba, its actions on the cardiovascular system have not been clarified. OBJECTIVES: To determine the effects of jabuticaba hydroalcoholic extract (JHE) on vascular smooth muscle (VSM) of isolated arteries. METHODS: Endothelium-denuded aortic rings of rats were mounted in isolated organ bath to record isometric tension. The relaxant effect of JHE and the influence of K(+) channels and Ca(2+) intra- and extracellular sources on JHE-stimulated response were assessed. RESULTS: Arteries pre-contracted with phenylephrine showed concentration-dependent relaxation (0.380 to 1.92 mg/mL). Treatment with K(+) channel blockers (tetraethyl-ammonium, glibenclamide, 4-aminopyridine) hindered relaxation due to JHE. In addition, phenylephrine-stimulated contraction was hindered by previous treatment with JHE. Inhibition of sarcoplasmic reticulum Ca(2+) ATPase did not change relaxation due to JHE. In addition, JHE inhibited the contraction caused by Ca(2+) influx stimulated by phenylephrine and KCl (75 mM). CONCLUSION: JHE induces endothelium-independent vasodilation. Activation of K(+) channels and inhibition of Ca(2+) influx through the membrane are involved in the JHE relaxant effect.