Physiological effects of magnesium in the guinea pig hearts

Chang, Sung-eun; Kim, Shang-jin; Kang, Hyung-sub; Kim, Jin-shang

Korean Journal of Veterinary Research 2001;41(3):311-317.

Sung-eun Chang, Shang-jin Kim, Hyung-sub Kang, Jin-shang Kim

Bio-Safety Research Institute, Chonbuk National University

기니픽 심장에서 magnesium의 생리학적 영향

장성은, 김상진, 강형섭, 김진상

전북대학교 생체안전성연구소

Abstract

In this work we have investigated the physiological effects of $MgCl_2$ in isolated atrium, papillary muscle, perfused heart and anesthesized guinea pig, The addition or infusion of $MgCl_2$ (0~20 mM or mg/kg) to perfused hearts and to anesthesized guinea pigs induced a marked and dose-dependent negative chronotropic effect. The sinoatrial node automaticity could also be reduced by $MgCl_2$. The addition of $MgCl_2$to isolated atria and to papillary muscles induced a marked and dose-dependent negative inotropic effect. The threshold voltage could be increased by $MgCl_2$in papillary muscle. Increasing $MgCl_2$ shortened the action potential duration (APD) in dose-dependent manner at 30% ($APD_{30}$) and 90% repolarization ($APD_{90}$) measured with conventional microelectrode technique in papillary muscle. In anesthesized guinea pig, the magnesium infusion resulted in a dose-dependent drop in blood pressure. These results suggested that magnesium is closely associated with cardiac physiological condition and exerts antiarrhythmic activities.

Key Words: magnesium, automaticity, action potential duration, threshold, contractility