A STUDY OF LOCALIZATION OF ATRIOPEPTINLIKE SUBSTANCE IN HEART VENTRICLES OF RAT EMBRYOS / 解剖学报

ABSTRACT

In this paper the distribution of the atriopeptin-like immunoreactive substance in the ventricles of rat embryos of 13-19 days old was investigated by immunohistochemistry and electron microscopy. The results showed that atriopeptin-like immunoreactive granules were located around the nucleus in some cardiocytes of the ventricles of rat embryos. Most of these cells were distributed in the pectinated or trabecular structures in the luminal surface of left ventricle and a few of them in the myocardium of left and right ventricles. In the same embryo ventricle muscle cells contained less immunoreactive granules than those in the atria. Under electron microscope the atrial specific granule-like granules were found mainly near the Golgi complex. Some cells were devoid of such granules in cytoplasm. In the ventricles the distribution of the muscle cells containing atrial specific granule-like granules corresponds to the sites of muscle cells containing atriopeptin-like substance from the immunohistochemical study. The results suggest that the so-called "atriopeptin" is also present in some ventricular myocytes in rat embryos. The presence of atriopeptin-like substance may be related to the unique type of embryonic circulation.