RESUMO
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.
RESUMO
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.
RESUMO
The distribution of atriopeptins in the rat's heart was studied with immunohis-tochemical method. It was noticed that the immuno-reactive granules existed in most atriaI muscle cells. It was abundant in the cytoplasm about the paranuclear position. The cardiocytes of both atrial appendages gave an intense immuno-reaetion. Most cardiocytes of right atrium were more reactive than those of left atrium. Parts of atrial muscle cells which were distributed in the back of the left atrium, atrial septum and coronary sinus were negative in reaction.
RESUMO
By means of the fluorescent histochemistry the small intense fluorescent (SIF) cells of the rat heart were identified under the fluorescent microscope, then the tissue containing these cells were prapared for electron microscopy. Ultrastracturally SIF cells were small in size and contained a lot of granules which can be distinguished into two types of electric density, and abundant number of mitocondria which appeared about 20 in each section of SIF cell at the nuclear level, and a large Golgi complex which consisted of 4-7 cisternae arranging in paralled array and some vesicles. Many single cisternae of rough endoplasmic reticulum were distributed in their cytoplasm. Adhesion zones and interdigitated processes were often observed between two SIF cells. Cholinergic nerves formed afferent synapses with SIF cells. SIF cells often occured near fenetrated capillaries. We found that the core of the granulated vesicles of some SIF cells were released into the perivascular space. These results indicated that SIF cells of the rat heart may have a local regulatory fnuction either as endocrinal or paracrinal cells.
RESUMO
Serial cryostat sections of five hearts and seven atria of rats were prepared. Falck's fluorescent histochemical method, and histological staining methods wereutilized in succession on the same section. Small intensely fluorescent cells in rat's heart are round, oval or polyhedral in shape. A few of them possess processes. These cells are found in the heart in four major forms: dense spheroid groups, loosely associated clusters, linear alignment, and isolated cells.The number of small intensely fluorescent cell varies between 442-664 cells in the adult rat's heart. 86-92% of them are localized in subepicardium of atrium, especially several areas on the dorsum of atrium. No small intensely fluorescent cell was found in endocardium. The rest of these cells are scattered in other parts of the heart. The distribution areas of atrial nerve ganglia and small intensely fluorescent cells in subepicardium are similar. There are no such cells in some atrial ganglia and there is no relation between the number of these cells in the ganglion and its size. Parts of these cells are often found near the blood vessels. Small intensely fluorescent cells are not morphologically associated with the conduction system in the rat.
RESUMO
The cells containing 5-hydroxytryptamine (5-HT) in the antrum of the SD rat's stomach were demonstrated by means of Sternberger's PAP immunohistochemical method and quantitative analysis were performed by means of Weibel's stereological method. The results were as follow: The 5-HT immunoreactive cells in the antrum of the rat's stomach were found only in the surface epithelium and the glandular epithelium of the mucosa. The volume density (V_v) was 0.0038?0.0004, the surface density (N_A) was 42.86+3.20 cells/mm~2 and the numerical density (N_v) was 2627.11?200.42 cells/mm~3. The distribution of 5-HT reactive cells showed an obvious regional difference. From the lesser curvature to the greater curvature of stomach, the cell density decreased gradually. The cell density was the highest in the lesser curvature: N_A was 59.96?3.48 cells/mm~2, Nv was 3729.23?216.89 cells/mm~3; and was second high in the two side walls: N_A was 42.39?3.48 cells/mm~2, Nv was 2647.18+216.57 cells/mm~3; and was lowest in the greater curvature: N_A was 29.39? 4.49 cells/mm~2, N_v was 1843.00?280.09 cells/mm~3. Most of the 5-HT immunoreaclive cells were found in the basal third section of the mucosa and the cell density was the highest. N_A was 92.33?6.92 cell/mm~2,N_v was 5336.28?410.22 cells/ mm~3; in the middle one third of the mucosa, the cell density came to next: N_A was 27.69?2.38 cells/mm~2, N_A was 1708.68?146.65 cells/mm~3; and in the superficial third section of the mucosa, the cell density was the lowest: N_A was 7.29?0.53 cells/mm~2, N_v was 457.00?35.44 cells/mm~3. In addition, a detailed observation on the morphology of the 5-HT immunoreactive cells was also undertaken.
RESUMO
The development and differentiation of myocardial cells in the atria of rat embryos from 11 to 19 days and neonates were studied by electron microscopy, particularly with reference to the occurrence and distribution of atrial specific granules in muscle cells. The results were as follows:Atrial specific granules were invisible in muscle cells of 11 days embryos and occurred only in a few muscle cells in 12 days embryos. Since then their size and number in muscle cells increased with development. The granules persisted during mitosis.In atria of embryos from the 12th day on two kinds of myocardial cells could be distinguished, the one containing specific granules and the other without. The former showed well developed Golgi complex and abundant rough endoplasmic reticulum. As development proceeds both types of cells showed increasing amount of myofilaments and mitochondria in their cytoplasm and following the same trend approaching maturity.