硝苯地平对运动诱发冠心病心肌缺血时TXB_2、6-酮-PGF_(1a)变化的影响

EFFECT OF NIFEDIPINE ON CHANGES OF PLASMA TXB_2 AND 6-KETO-PGF_1a DURING EXERCISE-INDUCED MYOCARDIAL ISCHEMIA IN PATIENTS WITH CORONARY HEART DISEASE

本文以放兔法测定50例正常人及30例心绞痛型冠心病者静息时和踏车运动试验时血浆丁XB_2、6-酮-PGF_(1α)浓度,冠心病组在口服硝苯地平(硝苯吡啶)45mg/日1周后重复检查。结果为:正常人运动时TXB_2稍增高,6-酮-PGF_(1α)显著增高;冠心病组TXB_2显著增高,6-酮-PGF_(1α)则无变化;硝苯地平可有效地抑制冠心病组运动时TXB_2增高,增大运动耐量,减轻心肌缺血。提示运动诱发心肌缺血可能与TXA_2-PGl_2平衡失调有关,硝苯地平可改善TXA_2-PGl_2平衡,缓解心肌缺血。

At rest and during bicycle exercise, plasma TXB_2 and 6-keto-PGF_1α were measured by radioimmunoassay in 50 normal subjects and 30 coronary heart disease (CHD) patients who developed myocardial ischemia during exercise. The examinations were repeated in the 30 CHD patients after a week of oral nifedipine treatment (45 mg per day). The results showed: Plasma TXB_2 levels slightly increased and 6-keto-PGF_2α levels significantly increased during exercise in normal subjects but plasma TXB_2 levels markedly increased and 6-keto-PGF_1α levels had no significant change during attack of exercise-induced myocardial ischemia in CHD patients. During exercise nifedipine significantly suppressed the enhancement of plasma TXB_2 levels, increased exercise tolerance and alleviated myocardial ischemia in CHD patients. This study suggests that TXA_2-PGI_2 imbalance during exercise might have some bearing on the mechanism of exercise-induced myocardial ischemia, and nifedipine could improve TXA_2-PGI_2 equilibrium and alleviate myocardial ischemia by inhibiting TXA_2 production.