Resumo

AVELLA, María Esperanza; LAPA, Antonio José; RIGGIO LIMA-LANDMAN, María Teresa  e  GUERRERO, Mario Francisco. Effects of the butanol-containing fraction from leaves of Calea prunifolia H.B.K. on blood pressure and smooth muscle responses of Wistar rats. Rev. colomb. cienc. quim. farm. [online]. 2014, vol.43, n.2, pp.284-299. ISSN 0034-7418.  https://doi.org/10.15446/rcciquifa.v43n2.54217.

The butanol-containing fraction from leaves of Calea prunifolia H.B.K. was obtained in order to examine cardiovascular effects on two distinct rat preparations. The responses elicited in isolated aorta and isolated vas deferens, were examined, as were the changes in blood pressure in anesthetized and conscious Wistar rats. In addition, the effects on angiotensin-converting enzyme activity in plasma and the effects on cytosolic calcium in cardiomyocytes and uterine cells were measured. Results show that the butanol-containing fraction from C. prunifolia (0.1-100 µg/mL) relaxes phenylephrine-induced contractions in isolated aorta (CI₅₀: 58 µg/mL), decreases the contractile response induced by noradrenaline in vas deferens, and shows a competitive antagonism profile (pA₂: 4.48, m: 1024). The butanol-containing fraction from C. prunifolia also decreases blood pressure in anesthetized rats in a dose-dependent manner (1-100 mg/kg, i.v.), yet is devoid of hypotensive effects in normotensive, conscious rats. In addition, C. prunifolia does not modify the hypertensive effects induced by the nitric oxide synthase inhibitor L-NAME, and it also does not affect the angiotensin-converting enzyme plasma activity nor the cytosolic calcium in cardiomyocytes and uterine cells. According to these results, C. prunifolia relaxes smooth muscle and vascular tone, favoring the decrease in blood pressure in rats via mechanisms related to alpha adrenergic inhibition.

Palavras-chave : Calea; antihypertensive; traditional medicine; vasodilation; vasorelaxant.

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