Cardiovascular effects of Hyptis fruticosa essential oil in rats

Abstract

In non-anesthetized normotensive rats, Hyptis fruticosa essential oil (HFEO, 5, 10, 20 and 40 mg/kg; i.v.) induced hypotension associated with tachycardia. In intact and isolated rings of rat superior mesenteric artery (control), HFEO (1 – 1000 μ g/ml, n =6, cumulatively) induced concentration-dependent relaxations of tonus induced by 10 μ M phenylephrine (Phe) (pD 2 =2.6±0.27; E max =64±8.3%). In denuded endothelium pre-contracted rings with Phe or K + -depolarizing solution (80 mM), the concentration – response curves to HFEO were not shifted (pD 2 =2.3±0.25 and 2.3±0.28, respectively), but their maximal responses were significantly ( P b 0.05 vs control) increased ( E max =122.3±18.2% and 92±3.6%, respectively). HFEO was also capable of antagonizing the concentration – response curves to CaCl 2 (3 μ M – 30 mM) in a dose-dependent manner.