胰岛素抵抗性高血压大鼠α_1肾上腺素受体亚型的改变

Alteration of α 1-adrenoceptor and its subtypes in heart and aorta of insulin-resistant hypertensive rats

目的和方法：用高糖喂养复制胰岛素抵抗性高血压（ｉｎｓｕｌｉｎ－ｒｅｓｉｓｔａｎｔｈｙｐｅｒｔｅｎｓｉｏｎ，ＩＲＨ）大鼠模型，用放射配体结合实验和离体左心房及主动脉收缩功能实验，观察ＩＲＨ大鼠α１肾上腺素受体（α１－ａｄｒｅｎｏｃｅｐｔｏｒ，α１－ＡＲ）及其３种亚型在心脏和主动脉的改变。结果和结论：ＩＲＨ大鼠与同龄ＳＤ大鼠相比：（１）心脏α１－ＡＲ密度下降４８％（Ｐ＜００５），而介导的正性变力效应不变。（２）心脏α１－ＡＲ３种亚型占α１－ＡＲ总数的比例和在介导心脏正性变力效应中的作用表现为α１Ｂ－ＡＲ增加，α１Ｄ－ＡＲ减少，而α１Ａ－ＡＲ不变。（３）介导主动脉收缩的α１－ＡＲ及各亚型对激动剂的敏感性及最大收缩效应均无明显改变。

AIM and METHODS:Insulin-resistant hypertension(IRH) was induced by feeding sucrose rich foods in rats.Alterations of α 1-adrenoceptor and its subtypes in heart and aorta were studied by radioligand binding assay and contractile response measurement.RESULTS and CONCLUSION:Compared with same aged normal rats,in IRH rats:(1) The density of cardiac α 1-adrenoceptor was reduced by 48%( P <0 05),without significant change of α 1-adrenoceptor-mediated positive inotropic response;(2)Ratio of the three subtypes of cardiac α 1-adrenoceptor and the contribution of each subtype on the agonist-induced response were changed,i.e. α 1B increased,α 1D decreased and α 1A not altered;(3)α 1-adrenoceptor and its subtypes were not changed in aortae.