| Background: The gene of β3-adrenoceptor has been successfully cloned in 1989. The early studies found that the β3-adrenoceptors mainly distribute in adipose tissues. Gauthier etc detected the β3-adrenoceptors mRNA in human myocardial fragments by RT-PCR in later studies. Pharmacological research found that there had no β3-adrenoceptors in rat hearts, but Dincer found it was not true. Although identification of the β3-adrenoceptors protein has been proved difficult, the study of the β3-adrenoceptors expression had great significance.Objectives: To study the expression of β3-adlrenoceptors proteins in rats' heart tissues after chronic myocardial ischemia.Methods: (1) Constructing the animal model: A left thoracotomy was performed. After pericardiotomy, left coronary artery was ligated between the pulmonary cone and the left auricular appendage. In 8 weeks, the hearts were excised. The left ventricle was divided into two parts at the transverse section parallel to the short axis of the heart. The apex parts were stored at refrigerator. The basis parts were fixed in phosphate buffered formalin and lastly embedded in paraffin. (2) Detection of echocardiography and hemodynamics: after being anesthetized with ketamine, LVPW, IVS, LVIDd, LVIDs, long axis and short axis of left ventricle was detected by two-dimemsional echocardiogram. Parameters of HR, SP DP AP. LVDP, LVSP LVAP LVEDP, +dp/dtmax -dp/dtmax were detected through BL-420E system. (3) Detection of β3-adrenoceptors: The status of myocardial ischemia after ligating coronary artery was observed under the microscope through paraffin section in 8 weeks. The proteins of β3-adrenoceptors were detected by immunohistochemistry and western blot in ventricular tissues from ischemia and non-ischemia hearts.Results: (1) Obvious scar formation of constructed chronic myocardial ischemia model was seen from gross observation by naked eye. Typical denaturalization and fibrosis were seen under the microscope through paraffin sectioning and hematoxylin and eosin staining. (2)The results of echocardiography showed there is no significance...
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