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 OBJECTIVE: To compare the distribution and characteristics of the M2 cholinergic receptors in atria and ventricles of rabbits. Methods: Immunohistochemistry was performed in rabbit myocardium using autoantibodies to the newly discovered cardiac M2 cholinergic receptor in patients with dilated cardiomyopathy and anti-receptor antibodies prepared by immunization with peptides from human M2 cholinergic receptors. Results: (1) Immunoreactive granules of M2 choline receptor mainly located in the cytoplasm far away from the nucleus; (2) There were obvious immunoreactive reactants in both atrial and ventricular myocytes, but there were significant differences in their distribution density. Atrial immunopositive granules Significantly more than the ventricles; ③ atropine, atrial ventricular cells immunoreactive products was significantly reduced, M2 choline receptor antibody and receptor binding sites can be partially blocked by M2 choline receptor antagonist. Conclusion: The M2 cholinergic receptors in the heart of rabbits are mainly distributed on the surface of atrial and ventricular myocytes. The density of M2 cholinergic receptors in the atrium is obviously larger than that in the ventricles. M cholinergic receptor antagonists have the effect of blocking the binding of the M2 cholinergic antibody to its receptor