Endogenous nitric oxide is involved in post-ischemic functional recovery induced by adenosine-enhanced ischemic preconditioning.

腺苷增强的缺血预适应(APC)提供心脏保护的确切机制仍不清楚。本研究探讨内源性一氧化氮(NO)在APC处理的兔心脏缺血再灌注早期功能恢复中的作用。兰根多夫灌流心脏进行全脑缺血30分钟，然后再灌流120分钟。测定再灌注期血流动力学参数和NO浓度。实验分为对照组(对照组)、全心缺血再灌注组(GI组)、全脑缺血5min再灌流5min组(缺血预适应组)、全脑缺血30min再灌流120min组(缺血预适应组)、缺血预适应前10ml肌注1 mmol/L腺苷10ml组(假手术组)、缺血预适应+硝基精氨酸甲酯(L组)灌流前30min组(L组)。APC组左室压一阶导数、左室舒张末压和冠脉流量较GI组和IPC组显著改善(p&lt；0.05)。APC组再灌流10min后NO浓度较其他组明显升高(p&lt；0.05)。这些作用可被使用L-NAME的NO合成酶抑制所消除。我们的结果提示内源性NO参与了APC对心脏缺血后功能的恢复。

The precise mechanism of cardioprotection afforded by adenosine-enhanced ischemic preconditioning (APC) remains unknown. The present study examines whether endogenous nitric oxide (NO) contributes to post-ischemic functional recovery during early reperfusion in the rabbit heart treated by APC. Langendorff perfused hearts underwent global ischemia for 30 minutes followed by reperfusion for 120 minutes. Hemodynamic parameters and NO concentrations were determined during reperfusion. The hearts were separated into groups as follows : perfusion without global ischemia for 180 minutes (Control) ; global ischemia and reperfusion (GI group) ; 5 minutes of global ischemia followed by 5 minutes of reperfusion then 30 minutes of global ischemia and 120 minutes of reperfusion (ischemic preconditioned (IPC) group) ; a 10 ml bolus injection of 1 mmol/L adenosine immediately before IPC (APC group) ; APC plus NG -Nitro-L-arginine methyl ester (L-NAME) for first 30 minutes of reperfusion (L-NAME group). The first derivative of left ventricular pressure, left ventricular end-diastolic pressure and coronary flow were significantly improved in the APC group as compared with the GI and IPC groups (p < 0.05). The NO concentration was significantly increased in the APC group compared with the other groups after 10 minutes of reperfusion (p < 0.05). These effects were abolished by NO synthase inhibition using L-NAME. Our results suggested that endogenous NO is involved in the post-ischemic functional recovery of the heart afforded by APC.