α_1受体对不同状态心肌细胞的作用

目的　通过激活和阻断不同状态心肌的α1 受体 ,探讨α1 受体的活化状态与不同状态心肌的关系。方法　采用Langedorff灌流技术复制动物模型。第 1个实验检验不同浓度的α1 受体激动剂 phenylephrine和阻断剂 prazosin(0 0 1、0 1、1、1 0、1 0 0 μmol·L- 1 )在缺血前 1 0min、缺血期和再灌注时的效应。第 2个实验研究 phenylephrine和 prazosin的时间依赖性。每组实验的末期 ,测量磷酸肌酸激酶、细胞凋亡和坏死情况。结果　 0 1、1 μmol·L- 1 的 phenylephrine可发挥最大效益 ,但prazosin浓度超过 1 0 μmol·L- 1 可产生有害作用。缺血前激活、缺血期间阻断α1 受体可保护心肌。再灌注时激活α1 受体效应不明确 ,但阻断α1 受体有害。结论　激动或阻断α1 受体所产生的效应与心肌的状态有关

The role of α1-adrenoceptors in different states of the cardiac myocyte

AIM The purpose of our study is to investigate the relationship between α 1 adrenoceptors and different status of the myocardium by activating or blocking α 1 adrenoceptors. METHODS Animal model was obtained by Langedorff perfusion with rat.In study 1 the dose responses to the α 1 adrenoceptors agonist phenylephrine and antagonist prazosin (0 01, 0 1, 1, 10, 100 μmol·L -1 ) administered for 10 min before ischemia, during ischemia, and during reperfusion were examined. The time dependance of phenylephrine and prazosin effects was investigated in study 2 At the end of each study, leakage of creatine kinase , apoptosis and cellular necrosis were measured. RESULTS phenylephrine is maximally beneficial at 0 1 and 1 μmol·L -1 , but prazosin is detrimental at concentrations above 10 μmol·L -1 . Activating α 1 adrenoceptors before ischemia was protective but detrimental during ischemia. Blocking α 1 adrenoceptors was beneficial during ischemia. Activating α 1 adrenoceptors during reperfusion did not significantly influence myocardial injury, but blocking it was detrimental during reperfusion. CONCLUSIONS The findings demonstrate that the effect of activating or blocking α 1 adrenoceptors depends on status of myocardium.