Effects of different concentrations of potassium and magnesium in cardiac arrest solution on the function of porcine coronary artery smooth muscle

Objective To study the effect of different concentrations of potassium and magnesium in cardiac arrest solution on the function of porcine coronary artery smooth muscle. Methods Twenty-four healthy Swedish domestic pigs were randomly divided into 4 groups, with 6 pigs in each group. The distal 1/3 of the left anterior descending coronary artery was dissected and cut into 1 mm long segments and then transferred into organ bath. In the first group, 16 mmol/L KCl-Krebs solution with accumulatively increasing concentrations of magnesium (0, 1.2, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 mmol/L) was added into the organ bath. The vasoconstrictor force of each magnesium ion concentration was recorded. In the second group, 23 mmol/L KCl-Krebs solution was added, and in the third group, 30 mmol/L KCl-Krebs solution was added, and in the fourth group, 40 mmol/L KCl-Krebs solution was added. The magnesium ion concentration was the same as that of the first group. The changes in the contractility of the coronary artery smooth muscle were evaluated in the four groups. Results The contractions of the coronary artery were significantly higher when the concentrations of potassium were higher. When the concentrations of potassium were constant, the contractions decreased as the concentrations of magnesium increased. If the contractions induced with KCl-Krebs solutions with 1.2 mmol/L, and the potassium-induced contractile force was 100%. When the contractile force was antagonized to 80%, the magnesium concentrations in the four groups respectively were 8, 10, 10, and 12 mmol/L. Conclusions The potassium concentration in the cardiac potassium high potassium cardioplegic solution is 16-23 mmol/L and the magnesium ion concentration is 8-12 mmol/L. It has little effect on the isolated porcine coronary vascular smooth muscle function, which is beneficial to the full perfusion of the cardioplegia and the protection of the myocardium. Key words: Cardiac arrest fluid; Coronary artery; Smooth muscle; Potassium ion; Magnesium ion