Protective effects of adenosine on acute myocardial ischemia

用戊巴比妥和安氟醚在空气中麻醉成年杂种狗。在左前降支上应用液压陷阱形成严重狭窄。低血压期滴注腺苷100 mcg/kg/min。血压显著降低，全身血管阻力（SVR）显著降低。心输出量增加，Emax无变化。心肌缺血时给予腺苷，心输出量、Emax维持较对照组好。缺血60 min后，分别在缺血区和非缺血区切除心脏。分别采用高效液相色谱法和DHA结合法测定细胞内腺苷、二磷酸腺苷、三磷酸腺苷浓度和肌细胞β受体密度。腺苷处理心肌与对照心肌在高能磷酸盐浓度和β受体密度方面无显著差异。结果表明，腺苷对急性缺血性心脏后负荷降低的继发性心肌泵功能有保护作用。细胞内高能磷酸盐和β受体密度的保存可能对维持该犬模型的心脏收缩功能没有重要作用。

Adult mongrel dogs were anesthetized with pentobarbital and enflurane in air. A hydraulic snare was applied over the left anterior descending artery to make a critical stenosis. In the hypotensive period, adenosine 100 mcg/kg/min was infused. Blood pressure was significantly decreased with a significant decrease in systemic vascular resistance (SVR). Cardiac output was increased with no change in Emax. When adenosine was given during myocardial ischemia, cardiac output, Emax were better maintained in adenosine-treated dogs than in the control group. After completion of the 60 min of ischemic period, the heart was excised and resected in ischemic and non-ischemic areas. The intracellular concentrations of adenosine, adenosine diphosphate, adenosine triphosphate, and beta-receptor density on the myocytes were measured using HPLC and H3-dihydroalprenol (DHA) binding assay respectively. There were no significant differences in high-energy phosphates concentrations and beta-receptor density between adenosine-treated myocardium and the control myocardium.The results suggested that adenosine preserved the myocardial pump function secondary to the decreased afterload in acute ischemic heart. Preservation of the intracellular high-energy phosphates and beta-receptor density probably did not play an important role to maintain cardiac systolic function in this canine model.