大鼠右心房肌和浆膜心包的电镜观察

目的探讨心房颗粒或心房肽的释放形式和在细胞外的转运途径,为此提供形态学方面的依据.方法 对大鼠右心耳及其对应区心包膜,进行透射和扫描电镜观察.结果心肌细胞内可见许多心房颗粒,有些颗粒向细胞表面突起.组织间隙中可见许多膜壳或膜碎片.心肌之间的毛细血管内皮连接紧密,为无窗孔的连续内皮型,管腔内常见红细胞.而毛细淋巴管内皮连接松散,可见重叠连接.心外膜表面的上皮细胞有丰富的微绒毛.心包膜壁层相邻的三个立方上皮细胞之间,存在较大的孔隙.结论心房颗粒从心房肌细胞的释放,可能存在一种连同颗粒界膜一起排出的整体释放形式.心房肽可以进入心肌之间的毛细淋巴管经淋巴转运,也可通过心外膜进入心包腔,再由心包膜淋巴管吸收和转运进入血液.

ELECTRON MICROSCOPIC OBSERVATION OF RIGHT ATRIAL MUSCLE AND SEROUS PERICARDIUM OF RATS

ObjectiveTo explore the releasing pattern and extracellular transport route of the atrial special secretory granules(ASG) or atrial natriuretic polypeptide(ANP), and offer the morphological evidences. MethodsThe right atrial appendage of rats and its opposite portion of the pericardium were observed by transmission and scanning electron microscope. ResultsThere are a lot of ASG in the myocardial cell. Some ASG project to the cellular surface, and many membranous shells and fragments could be seen in tissue space. The endothelium of blood capillaries among the myocardial cells interconnects tightly. And the type of endothelium is continuous without fenestra. There often are red blood cells in the lumen of blood capillaries. But the endothelium of lymphatic capillaries interconnects loosely. And the overlap junction could be seen. There are rich microvilli on the surface of epithelial cells in the epicardium. Among three consecutive cuboidal cells of the parietal pericardium seems to exist a pore. ConclusionASG released from the atrial myocardial cells seem to be a whole releasing pattern, which is together released with granular limiting membrane. And ANP may enter the lymphatic capillary among the myocardial cells and be transported by the lymphatic system. Also it seems to directly enter the pericardial cavity through the epicardium, then be absorbed and transported by the lymphatic vessel of the pericardium into blood.