AN ATRIOPEPTIN IMMUNOHISTOCHEMICAL STUDY OF ATRIAL MUSCLE CELLS OF RAT EMBRYOS AND NEONATES / 解剖学报

ABSTRACT

The occurrence and distribution of the atrial muscle cells containing atriopeptinimmunoreactive granules were studied in rat embryos and newborn rats with immunohistochemistry. The results showed that immunoreactive granules occurred in a few atrial muscle cells of embryos at 13 days old but they were not found in those cells at 11 and 12 days. With development of the embryos, the number of cells containing immunoreactive granules in atrium increased and their granules became more abundant and located mainly around the nucleus. Most of the granulated atrial muscle cells distributed in trabecular structure of the luminal surface of atria. They gradually decreased in number towards the pericardial side. The nongranulated atrial muscle cells mainly located near the pericardium and in atrial septum. The results suggested that the specific differentiation of atrial muscle cells occurred at early period of rat embryos, some cells became atriopeptin immunoreactive positive cells, while the others remained as negative cells. The feature of the differentiation of atrial muscle cells may reflect the functional development of the atria.