兔心房和心室M_2胆碱受体分布特性的比较研究

目的 :对比观察了兔左右心房和心室M2 胆碱受体的分布位置及其特性。方法 :采用在扩张型心肌病患者新发现的心脏M2 胆碱受体自身抗体与用人M2 胆碱受体肽段经免疫制备的抗受体抗体在兔心肌进行免疫组织化学研究。结果 :①M2 胆碱受体的免疫反应阳性颗粒主要位于远离胞核的胞浆内 ;②心房和心室肌细胞均存在明显的免疫阳性反应物 ,但其分布密度存在有明显差异 ,心房免疫阳性颗粒明显多于心室 ;③用阿托品后 ,心房心室细胞的免疫阳性反应产物明显降低 ,M2 胆碱受体抗体和受体结合的位点可部分被M2 胆碱受体拮抗剂阻断。结论 :兔心脏M2 胆碱受体主要分布于心房和心室肌细胞的表面 ,心房M2 胆碱受体密度明显大于心室。M胆碱受体拮抗剂具有阻滞M2 胆碱受体抗体和其受体结合的效应

Immunocytochemical studies of M2 muscarinic receptors in rabbit atria and ventricles using anti-peptide antibodies

Objective: The purpose of this study is to research the localization and density of M 2 muscarinic receptors in rabbit atria and ventricles. Methods: The localization and density of M 2 muscarinic receptors were measured by immunocytochemical techniques with anti peptide antibodies against the second extracellular loop of human muscarinic receptor 2.Results: It was shown that the positive immunoreaction of M 2 muscarinic receptor was characterized by brown yellow granules of variable size and shape,which were located mainly on the cell surface and in the cytoplasm far from nuclei.The positive immunoreactive substances appeared in both atrial and ventricular myocytes,with the density being greater in atria than in ventricles.Pre incubation with atropine,but not carbachol,significantly reduced the intensity of positive immunoreactivity.This indicates that the binding of antibody to receptor site can be partially blocked by M 2 muscarinic receptor antagonist. Conclusion: M 2 muscarinic receptors were localized on the surface of both atrial and ventricular myocytes in guinea pig with the density of receptor sites in atria being greater than in ventricles and that the binding of antibody to receptor site can be partially blocked by M 2 antagonist.