Liu J, Chen R, Casley D J, Nayler W G
Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
Am J Physiol. 1990 Mar;258(3 Pt 2):H829-35. doi: 10.1152/ajpheart.1990.258.3.H829.
The effect of aerobic perfusion, of up to 90 min global ischemia, and of reperfusion on 125I-labeled porcine endothelin (125I-ET-1) binding site density (Bmax), affinity (KD), and selectivity was investigated using cardiac membranes harvested from adult Sprague-Dawley rats. Membranes from nonperfused hearts bound 125I-ET-1 with a Bmax of 117.0 +/- 8.8 fmol/mg protein, a KD of 0.076 +/- 0.005 nM, and a Hill coefficient approaching unity. Neither aerobic perfusion nor 10 min of normothermic ischemia and subsequent reperfusion altered these binding parameters. The extension of the ischemic episode increased Bmax (23, 32, 62, and 60% increase after 20, 30, 60, and 90 min ischemia, respectively). Reperfusion further increased Bmax (P less than 0.01 at 15 min reperfusion after 20 and 30 min ischemia, and after 30 min reperfusion following 60 min ischemia) without changing selectivity. Affinity was reduced after 60 (P less than 0.05) and 90 (P less than 0.01) min ischemia. Ischemia at 22 degrees C had no effect on the density or affinity of these binding sites.
使用从成年Sprague-Dawley大鼠获取的心脏膜，研究了长达90分钟全心缺血的有氧灌注、再灌注对125I标记的猪内皮素（125I-ET-1）结合位点密度（Bmax）、亲和力（KD）和选择性的影响。未灌注心脏的膜结合125I-ET-1时，Bmax为117.0±8.8 fmol/mg蛋白，KD为0.076±0.005 nM，希尔系数接近1。有氧灌注、10分钟常温缺血及随后的再灌注均未改变这些结合参数。缺血时间延长会增加Bmax（分别在缺血20、30、60和90分钟后增加23%、32%、62%和60%）。再灌注进一步增加Bmax（在20和30分钟缺血后15分钟再灌注时，以及60分钟缺血后30分钟再灌注时，P<0.01），且不改变选择性。缺血60分钟（P<0.05）和90分钟（P<0.01）后亲和力降低。22℃缺血对这些结合位点的密度或亲和力无影响。
