Department of Pharmacology and the Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
J Pharmacol Exp Ther. 2012 Jan;340(1):210-7. doi: 10.1124/jpet.111.187559. Epub 2011 Oct 19.
Adenosine is increased in ischemic tissues where it serves a protective role by activating adenosine receptors (ARs), including the A₃ AR subtype. We investigated the effect of N-{2-[(3,4-dichlorophenyl)amino]quinolin-4-yl}cyclohexanecarboxamide (LUF6096), a positive allosteric modulator of the A₃ AR, on infarct size in a barbital-anesthetized dog model of myocardial ischemia/reperfusion injury. Dogs were subjected to 60 min of coronary artery occlusion and 3 h of reperfusion. Infarct size was assessed by macrohistochemical staining. Three experimental groups were included in the study. Groups I and II received two doses of vehicle or LUF6096 (0.5 mg/kg i.v. bolus), one administered before ischemia and the other immediately before reperfusion. Group III received a single dose of LUF6096 (1 mg/kg i.v. bolus) immediately before reperfusion. In preliminary in vitro studies, LUF6096 was found to exert potent enhancing activity (EC₅₀ 114.3 ± 15.9 nM) with the canine A₃ AR in a guanosine 5'-[γ-[³⁵S]thio]triphosphate binding assay. LUF6096 increased the maximal efficacy of the partial A₃ AR agonist 2-chloro-N⁶-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide and the native agonist adenosine more than 2-fold while producing a slight decrease in potency. In the dog studies, administration of LUF6096 had no effect on any hemodynamic parameter measured. Pretreatment with LUF6096 before coronary occlusion and during reperfusion in group II dogs produced a marked reduction in infarct size (∼50% reduction) compared with group I vehicle-treated dogs. An equivalent reduction in infarct size was observed when LUF6096 was administered immediately before reperfusion in group III dogs. This is the first study to demonstrate efficacy of an A₃ AR allosteric enhancer in an in vivo model of infarction.
腺嘌呤核苷在缺血组织中增加，通过激活包括 A₃AR 亚型在内的腺嘌呤核苷受体（ARs）发挥保护作用。我们研究了 N-{2-[(3,4-二氯苯基)氨基]喹啉-4-基}环己烷甲酰胺（LUF6096）对巴比妥麻醉犬心肌缺血/再灌注损伤模型中梗死面积的影响，LUF6096 是 A₃AR 的正变构调节剂。犬接受 60 分钟的冠状动脉闭塞和 3 小时的再灌注。通过宏观组织化学染色评估梗死面积。研究包括三个实验组。I 组和 II 组分别给予两次载体或 LUF6096（0.5 mg/kg 静脉推注），一次在缺血前给予，另一次在再灌注前给予。III 组在再灌注前给予单次 LUF6096（1 mg/kg 静脉推注）。在初步的体外研究中，LUF6096 在犬 A₃AR 的鸟嘌呤 5'-[γ-[³⁵S]硫]三磷酸结合测定中表现出很强的增强活性（EC₅₀ 114.3±15.9 nM）。LUF6096 使部分 A₃AR 激动剂 2-氯-N⁶-(3-碘苄基)腺苷-5'-N-甲基羧酰胺和天然激动剂腺苷的最大功效增加了 2 倍以上，而效力略有降低。在犬研究中，LUF6096 给药对测量的任何血流动力学参数均无影响。与 I 组载体处理的犬相比，在 II 组犬中，在冠状动脉闭塞前和再灌注期间给予 LUF6096 预处理可显著减少梗死面积（减少约 50%）。当在 III 组犬中立即在再灌注前给予 LUF6096 时，观察到梗死面积的等效减少。这是第一项证明 A₃AR 变构增强剂在体内梗死模型中有效性的研究。
