摘要
目的 观察缺血再灌注损伤 (IRI)心肌细胞核兰尼定受体 (Ry R)结合特性改变。方法 雄性Wistar大鼠随机分为 IRI组和假手术 (Sham )组 ,结扎冠状动脉左主干建立 IRI模型 ,~3H -Ryanodine饱和结合法分析分离的心肌细胞核上 Ry R最大结合容量 (Bmax)和解离常数 (K d)。结果 大鼠心肌细胞核存在高亲和力的 Ry R,IRI组较 Sham组 Bmax降低 2 9% (P<0 .0 1) ,K d差异无显著性 (P>0 .0 5 )。IRI组和 Sham组心肌细胞核经佛波酯 (PMA) +磷脂酰丝氨酸 (PS)处理后 ,Bmax均显著增加 (P均 <0 .0 1) ,但 IRI组的增加幅度较小 (P<0 .0 1) ;IRI组和 Sham组心肌细胞核经 Ca2 +钙调素 (Ca M)处理后 ,Bm ax均降低 (P均 <0 .0 5 ) ,但 IRI组降低幅度较小 (P<0 .0 1) ;上述处理对两组 K d均无显著影响 (P均 >0 .0 5 )。结论 IRI心肌细胞核 Ry R的 Bm ax呈降低趋势 ;经 PMA+PS和 Ca^(2 +) -Ca M处理后 ,Bmax的改变削弱 ,而 K d无改变。
Objective To investigate the changes in binding features of 3HRyanodine cardiomyocytic nuclei in reperfusion injury in the rat, and the effects of phosphorylation regulation on the binding characteristics. Methods Healthy male Wistar rats were randomly divided into ischemia/reperfusion injury(IRI) group and shamoperation group. IRI model was reproduced by ligating the left main coronary artery for 30 minutes followed by reperfusion of the heart for 3 hours, while in the shamoperation group the animals underwent a thoracotomy only for 3 5 hours. Cardiomyocytic nuclei were isolated by sucrose density gradient centrifugation. The maximum binding capacity (Bmax) and the dissociating ratio ( K d) of Ryanodine receptors(RyRs) were measured by radioligand binding analysis as well as Scatchard plot. Results There was a high affinity of RyRs to bind with 3HRyanodine on the nuclear wall of rat cardiomyocytic nucleus. Compared with that of the shamoperation group, Bmax of RyRs of IRI cardiomyocytic nuclei was decreased by 29%( P <0 01), but there was no difference in K d between two groups( P >0 05). With phosphorylation by activating the endogenous protein kinase C(PKC) with phorbol myristate acetate (PMA)+phosphatidyl serine(PS), Bmax of both sham and IRI groups were increased markedly ( P <0 01), but in the latter group it was less increased( P <0 01). With phosphorylation by Ca 2+ calmodulin (CaM), Bmax was decreased in both shamoperation and IRI groups(both P <0 05), but was less decreased in the latter( P <0 01). However, both PMA+PS and Ca 2+ CaM did not change the K d of nuclear RyR in either group(both P >0 05). Conclusion After IRI, Bmax of 3HRyanodine of cardiomyocytic nuclei is decreased and the impact of PMA+PS and Ca 2+ CaM on the Bmax is impaired, but the affinity of 3 HRyanodine to cardiomyocytic nuclei is not altered under above circumstances.
出处
《中国危重病急救医学》
CAS
CSCD
北大核心
2005年第3期146-149,共4页
Chinese Critical Care Medicine
基金
国家自然科学基金资助项目 (3 0 10 0 0 70 )
