Analysis of pr- ram of porcine cardiac ischemia and the recovery process in coronary arterial occlusion and recanalization using 31P-MRS

为探讨缺血心肌的代谢异常，应用在体动脉压门控和呼吸门控31 P磁共振波谱技术，对无侧支循环的缺血猪心高能磷酸盐、无机磷酸盐和细胞内pH值的变化进行了动态定量研究。方案也针对普萘洛尔预处理（0.6mg/kg i. v.）和卡替洛尔治疗前和治疗后（10 μ g/kg i. v.）β-受体阻滞剂和维拉帕米（200 μ g/kg），以确定它们对缺血心肌代谢的影响。在非治疗组，磷酸肌酸迅速耗尽缺血后20分钟，40分钟，ATP和intattacellular pH值逐渐下降到10 - 11%的控制和5.90 - 0.26，分别，和无机磷酸盐上升到303 - 43%的控制。普萘洛尔、维拉帕米和卡替洛尔预处理组ATP浓度在阻断20分钟时较高，阻断40分钟时保护作用消失。对照组和治疗组的双乘积无显著差异。这表明β受体阻滞剂和Ca拮抗剂对缺血心肌的有益作用是由于对存活的缺血心肌细胞的直接作用。再灌注20分钟后，磷酸肌酸，pH和无机磷酸盐迅速恢复正常。再灌注120分钟后，对照组和后处理组的ATP水平无明显变化。预处理组再灌注120分钟后ATP浓度恢复正常。这表明，有益效果是由于闭塞期间的保护作用。

In an attempt to define the metabolic abnormalities of ischemic myocardium, the changes in high energy phoshates, inorganic phosphate and intracellular pH were serially and quantitatively evealuated in ischemic porcine hearts habing no collateral circulation using arterial pressure and respiration gated in vivo 31P magnetic resonance spectroscopy. The protocol was also modified for propranolol pretreatment (o.6mg/kg i.v.) and carteolol pre-and post-treatment (10mug/kg i.v.) as beta-blockers and verapamil (200mug/kg) to define their effects on the metabollsm of ischemic myocardium. In the non-treated group, creatine phosphate was repidly depleted by 20 miutes after ischemia; by 40 minutes, ATP and inttacellular pH gradually decreased to 10 11% of control and to 5.90 0.26, respectively, and inorganic phosphate rose to 303 43% of control. In the propranolol, and verapamil and carteolol pre-treated-group, the concentrations of ATP were higher at 20 minute occlusion, and the protective effect disappeared at 40 minute occlusion. There was no significant difference of double product between control and treated groups. This suggests that the beneficial effect of beta-blocker and Ca antagonist on ischemic myocardium is due to direct effect to viable ischemic myocytes. In reperfusion after 20 minute occlusion, creatine phosphate, pH and inorganic phosphate were normalized rapidly. In control and post treated group, ATP level did not change ecen in 120 minute reperfusion. In pretreated group, however, the concentration of ATP was normalized after 120 minute of reperfusion. This suggested that the beneficial effect is due to the protective effect during occlusion.