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Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: pH-dependent modulation of intracellular free magnesium ions with ion- selective electrodes in papillary muscle of guinea pig | J. Vet. Set. 2006 7 1 31-36 JOURNAL OF Veterinary Science pH-dependent modulation of intracellular free magnesium ions with ion-selective electrodes in papillary muscle of guinea pig Shang-Jin Kim1 In-Gook Cho1 Hyung-Sub Kang1 2 3 Jin-Shang Kim1 2 Department of Pharmacology Toxicology College of Veterinary Medicine Chonbuk National University Jeonju 561-756 Korea 2Bio-Safety Research Institute Chonbuk National University Jeonju 561-756 Korea 3 Center for Healthcare Technology Development Chonbuk National University Jeonju 561-756 Korea A change in pH can alter the intracellular concentration of electrolytes such as intracellular Ca23 and Na Na3I that are important for the cardiac function. For the determination of the role of pH in the cardiac magnesium homeostasis the intracellular Mg23 concentration Mg23 membrane potential and contraction in the papillary muscle of guinea pigs using ion-selective electrodes changing extracellular pH pH J or intracellular pH pH were measured in this study. A high CO2-induced low pH causes a significant increase in the Mg23 and Na3 which was accompanied by a decrease in the membrane potential and twitch force. The high p I I had the opposite effect. These effects were reversible in both the beating and quiescent muscles. The low pH ơ-induced increase in Mg23 occurred in the absence of Mg23 . The Mg23 was increased by the low pH induced by propionate. The Mg23 was increased by the low pH induced by NH4Cl-prepulse and decreased by the recovery of pH induced by the removal of NH4C1. These results suggest that the pH can modulate Mg23 with a reverse relationship in heart probably by affecting the intracellular Mg23 homeostasis but not by Mg23 transport across the sarcolemma. Key words ion-selective electrodes guinea pig magnesium papillary muscle Although the biophysiological importance of magnesium has long been recognized 28 since it was first demonstrated to play an essential role in mammals 75 years ago 19 the mechanism for how .
