THE PECUALIARITIES OF SECRETORY ACTIVITY OF MYOENDOCRINE CELLS COR PULMONALE IN DIFFERENT TYPES OF BLOOD SUPPLY

Abstract

In recent years, researchers are increasingly paying attention to atrial myoendocryne cells producing natriuretic hormone that is active in water-salt homeostasis of the organism. Besides diuretic and natriuretic functions, this hormone is an antagonist of the system renin-angiotensin-aldosterone and remodeling walls of arteries, regulates vascular resistance. It should be noted that in hypertension in the large and small circles and the cor pulmonale a structure and function of mioendocryne cells were studied enough.

The aim of the study – to examine the peculiarities of secretory activity of atrial myoendocrine cells in cor pulmonale with different types of blood supply.

Materials and Methods. Myoendocrine cells of 22 mature male pigs of vietnam thorough-bred, which had been divided into 6 groups were studied. The first group consisted of 4 intact heart (18.2 %), with prevalence right coronary artery, secоnd – similar 3 organs (13.6 %) with prevalence left coronary artery, the third – three intact heart (13.6 %) with a uniform distribution of coronary arteries, fourth – 5 cor pulmonale (22.8 %) with prevalence right of coronary artery, the fifth – 4 cor pulmonale (18.2 %) with prevalence left of coronary artery, the sixth – 3 pulmonary heart disease (13.6 %) with uniform distribution coronary arteries. Hypertension in the pulmonary circulation and cor pulmonale were modeled in pigs by performing right pulmonectomy. One month from the beginning of the experiment we carried out euthanasia by phlebotomy of animals in terms of thiopental natrium anesthesia. The heart from the chest was removed, cut by H. Avtandilov and separate weighing of the heart chambers and planimetry of endocardial surfaces was held. On the left and right atria after proper fixation and conduction we made ultrathin sections that were examined in the electron microscope PEM-125K. Using stereometric methods in mioendocryne cells in the left and right atria we determined the relative amounts of secretory granules and per cent of young, mature and diffusing secretory granules. Quantitative indicators were treated statistically.

Results and Discussion. A separate weighing and planimetry heart chambers found that a month after the right-pulmonectomy increased mass of the heart and their spatial characteristics dominated hypertrophy and dilatation of the right ventricle. The results showed the development of cor pulmonale. Comprehensive analysis of the data revealed that in experimental conditions simulated quantitative morphological characteristics of cell secretory granules in mioendocryne cells significantly changed. It was established that the postresection arterial pulmonary hypertension and cor pulmonale secretory activity varied significantly. In the myoendocryne cells the number of secretory granules decreased among them young and mature structures and diffusing increase, indicating increased allocation natriuretic hormone to maintain homeostasis. It should be also indicated that the quantitative changes of greatest secretory granules were in the right atrium of the heart with in the right- and left types of blood supply.

Conclusions. Thus, the results of the research show that in a long postresective hypertension in the pulmonary circulation and cor pulmonale significantly deteriorates secretory activity of myoendocryne cells and disturb relation between types of secretory granules. The most pronounced decrease secretory activity of these structures in the studied experimental conditions found in the right atrium and in dominance with prevalence right and left of coronary artery types of blood supply of the heart.