目的　探讨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对大鼠左右心房和心室M2 胆碱受体的分布位置及其特性的影响。方法　利用免疫组织化学方法及图象分析技术测定M2 胆碱受体在大鼠心房和心室肌细胞的分布位置及其密度的变化。结果　M2 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 ;心房和心室肌细胞均明显存在有免疫阳性反应产物 ,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。用阿托品后 ,心房心室细胞的免疫阳性反应产物明显降低。结论　大鼠M2 胆碱受体主要位于心房和心室肌细胞表面 ,心房M2 胆碱受体的分布密度明显大于心室 ,M2 胆碱受体抗体和受体结合的位点可部分被M2 胆碱受体拮抗剂阿托品所阻断 Objective To investigate the distribution of M2 cholinergic receptors in the left and right atriums and ventricles of rats induced by newly discovered cardiac M2 cholinergic autoantibodies in patients with dilated cardiomyopathy and with anti-receptor antibodies prepared by immunization with peptide fragments of human M2 cholinergic receptors Location and its characteristics. Methods Immunohistochemistry and image analysis were used to determine the distribution and density of M2 cholinergic receptors in rat atrial and ventricular myocytes. Results The immunoreactive granules of M2 choline receptor mainly located in the cytoplasm far away from the nucleus. There were immunopositive reaction products in both atria and ventricular myocytes, but there were significant differences in distribution density and atrial immunopositive granules In the ventricle. With atropine, atrial ventricular cells immunoreactive products significantly reduced. Conclusion The rat M2 cholinergic receptors are mainly located on the surface of atrial and ventricular myocytes. The distribution density of atrial M2 cholinergic receptors is significantly greater than that of the ventricular. The site of M2 cholinergic receptor antibody and receptor binding may be partly affected by M2 cholinergic receptors Blocking atropine antagonist