间硝苯地平对老龄肾性高血压大鼠心肌和脑微粒体Na+,K+-ATP酶,Ca2+-ATP酶和Mg2+-ATP酶活性的影响

间硝苯地平(m-Nif,ig20mg·kg^-1·d^-1持续给药9周)可显著降低老龄肾性高血压大鼠(RVHR)血压和左室重量(P<0.01),增高心、脑微粒体Na⁺,K⁺-ATP酶和Ca²⁺-ATP酶活性(P<0.01),降低Mg²⁺-ATP酶活性,体外量效关系研究发现,m-Nif在较高剂量(10～1000μmol·L^-1)时可增高RVHR心脑微粒体Na⁺,K⁺-ATP酶和Ca²⁺-ATP酶活性,且随剂量增加而增高。上述结果表明,m-Nif可改善老龄RVHR心脑微粒体Na⁺,K⁺泵和Ca²⁺泵功能。

EFFECTS OF m-NIFEDIPINE ON ACTIVITIES OF NA+,K+-ATPase,Ca2+-ATPase AND MG2+-ATPase IN MYOCARDIUM AND BRAIN OF ELDERLY RENOVASCULAR HYPERTENSIVE RATS

Clipping the left renal artery induced marked hypertension and hypertrophy of theleft ventricle in elderly(24-month-old) rats. m-Nifedipine(m-Nif,ig20mg·kg^-1,qd×9wk)significantly decreased the systolic blood pressure and the weight of the left ventricle in therenovascular hypertensive rats(RVHR).In RVHR,the activities of Na⁺,K⁺-ATPase and Ca²⁺-ATPase in microsomes of themyocardium and brain Were reduced significantly compared with those in sham-operated rats.m-Nifwas found to increase the activities of these enzymes of the myocardium and brain in elderly RVHR(P>0.01).m-Nif 10～1000μmol·L^-1 in vitro elevated the activities of Na⁺,K⁺-ATPase andCa²⁺-ATPase in the myocadium and brain of RHVR.On the contrary,the myocardial and cerebral Mg²⁺-ATPase activities were higher in RVHR than in sham-operated rats.m-Nif was shown todepress markedly this enzyme both in vivo and in vitro.These results indicate that m-Nif can improvethe activities on Na⁺,K⁺-ATPase and Ca²⁺-ATPase in the myocardium and brain in elderly RVHR.