Efeito inotrópico exercida pelo derivado de brucina em um modelo de corações isolados de ratos

Few data exist with respect to the effects of brucine and its derivatives at a cardiovascular level; furthermore, the molecular mechanism and its site of cellular action are still unclear. In order to provide additional information about this phenomenon, the effect induced by a brucine derivative on perfusion pressure, vascular resistance and left ventricular pressure was evaluated in anisolated rat heart at constant flow (Langendorff model). Theresults showed that: 1) The brucine derivative [1×10^-9 mM] increased perfusion pressure and vascular resistance in comparison with the brucine [1×10^-9 mM] and the control conditions; 2) the effects of brucine derivative [1×10^-9 to 1×10^-4 mM] on intraventricular pressure were not inhibited by metoprolol, prazosin or nifedipine at a 1×10^-6 mM dose; 3) furosemide [1×10 ^-6 mM] blocked the effects exerted by the brucine derivative [1×10^-9 a 1×10^-4 mM] on intraventricular pressure. In conclusion, the activity exerted by the brucine derivative on perfusion pressure, vascular resistance and left ventricular pressure, involves inhibition of Na⁺/K⁺-ATPase, consequently resulting in indirect changes in intracellular calcium levels and subsequently inducing a positive inotropic effect.