DIETARY　MAGNESIUM　DEFICIENCY　INCREASES　LEVELS　AND　FUNCTION　OF　Giα　IN　THE　RAT　HEART　AFTER　MYOCARDIAL　INFARCTION

作     者：石冰 

出 版 物：《Journal of Pharmaceutical Analysis》 (药物分析学报（英文版）)

年 卷 期：1995年第9卷第2期

页      面：197-198页

学科分类：10[医学] 

主　　题：G proteins magnesium deficiency myocardial infarction heart function hypomagnesemia Cardiovasc 

摘      要：Magnesium(Mg) is crucial for the function of G proteins which play important roles in mediating the inotropic effects of β adrenergic agonists in the heart and are alteredin heart *** study was performed to determine whether or not dietary Mg deficiency alters functional activity and levels of the two major ventricular G proteins, Gia and Gsa in the heart after myocardial infarction(MI).Six week old rats were fed a Mg adequate or deficient diet for 6 *** the end of week 3,MI was induced by coronary artery ligation.A sham operation was performed as *** surgery,surviving animals were maintained on their assigned diets for another 3 ***,cardiac function was *** hypomagnesemia and increased plasma catecholamine level were observed in all animals fed the Mg deficient diet.A significant reduction of ruyocardial Mg concentration accompanied by elevated plasma and myocardial calcium concentrations was observed in MI animals with existing Mg deficiency *** fed the Mg adequate *** function was impaired in MI rats and further reduced in MI rats with existing Mg deficiency. Gia level was not altered by either Mg deficiency or MI alone,but was dramatically elevated in animals with combined Mg deficiency and MI (9. 9±0.7 arbitrary ***-1 protein) as compared to MI alone (5.8±0. 6,P0.05 )and Mg deficiency alone(6.1± 0.8,P0.05 ). Gsa level did not differ between ***,GppNHp-and forskolin-but not fluoride-, stimulated adenylyl cyclase activity was signifcantly reduced in MI animals with existing Mg deficiency indicating increased functional activity of *** findings suggest that dietary Mg deficiency increases the expression and functional ac tivity of Gia in the heart after MI, while levels and function of Gsa are not compromised during dietary Mg deficiency either with or without MI.