Fresh and Decayed Stem Juice of Musa acuminata x balbisiana (Musa paradisiaca) Reduce the Force and Rate of Contractility of an Isolated Perfused Rabbit Heart

Abstract

Background: Decaying stem juice of Musa acuminata × balbisiana is commonly used by local communities and traditional herbalist in Central Uganda in the management of cardiovascular conditions like hypertension. Aims: The study investigated the ionotropic and chronotropic effect of fresh and decaying stem juice of Musa acuminata × balbisiana on the isolated perfused rabbit heart. Materials and Methods: Methods. Study Design: An experimental study. Place and Duration of Study: Study was done at the Dept of Pharmacology & Therapeutics Pharmacology Lab between December 2012 to March 2013. Experimental Procedure: An experimental study determined the effects of fresh and decayed stem juices of Musa acuminate X balbisiana on the rate and force of contraction of an isolated rabbit heart using Langendorff’s heart perfusion experiment and methods. The heart rate (beats/minute) was determined. The force of contraction of the heart was determined by measuring the height of each peak on the kymogram. Results: The force and rate of contractility of an isolated perfused rabbit decreased with increasing doses of the stem juice from 0.156 mg/mL to 100mg/mL for both the fresh and decayed stem juice of M. acuminata. The decrease could be associated with the high [K+] ions that decrease the membrane potential or cause hyperpolarization the myocardial cell membranes leading to reduced force and rate of heart contractility. The effect of the fresh stem juice was short lived and at very high concentrations, it caused a cardiac arrest while the effect of the decayed stem juice was prolonged. Conclusion: Fresh and decayed stem juice of Musa acuminata × balbisiana have compounds that cause a negative ionotropic and chronotropic effect on an isolated perfused rabbit heart.