RESUMO
The system of cardiac natriuretic peptides (NP) is a very important factor opposing the effects of the rennin-angiotensin-aldosterone system (RAAS), sympathoadrenal system and vasopressin to reduce blood pressure. In the present study, we analyzed the release of atrial and brain natriuretic peptides in the myocytes of the right atrium in rats by the quantitative morphometric method using double immunocytochemical labeling of atrial granules comprising NP in vasorenal hypertension induced by the renal artery ligation. The decrease in the total amount of secretory granules in atrium myocytes by 18% was detected on the 30th day after the operation. The number of the A-type granules was reduced by 53%, and the number of B-type granules was increased by 64% in comparison with the intact animals. Our data indicate activation of NP secretion in vasorenal hypertension. The results suggest that high arterial pressure might be explained by reduced expression of NP receptors in this pathology.
Assuntos
Fator Natriurético Atrial/metabolismo , Grânulos Citoplasmáticos/metabolismo , Átrios do Coração/metabolismo , Hipertensão Renovascular/metabolismo , Miócitos Cardíacos/metabolismo , Peptídeo Natriurético Encefálico/metabolismo , Animais , Imuno-Histoquímica , Masculino , Ratos , Ratos EndogâmicosRESUMO
Vasorenal hypertension in rats resulted in increase of arterial pressure, the plasma concentration of creatinine and potassium. By EM immunocytochemistry we have demonstrated that atrial natriuretic peptide (ANP) was kept in the granules of secretory cardiomyocytes of the right atrium. It has shown that cardiomyocytes released ANP by means of diffusion. The increased secretion of atrial natriuretic peptide has been detected in blood. However the physiological effects this peptide probably was impaired due to the reducing of the density of natriuretic peptide receptors.
Assuntos
Fator Natriurético Atrial/sangue , Hipertensão/sangue , Hipertensão/patologia , Miócitos Cardíacos , Vesículas Secretórias , Animais , Pressão Sanguínea , Hipertensão/fisiopatologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/ultraestrutura , Ratos , Receptores do Fator Natriurético Atrial/metabolismo , Vesículas Secretórias/metabolismo , Vesículas Secretórias/ultraestruturaRESUMO
Ultrastructural changes in the colorectal mucosa in response to chronic contact with the urine were demonstrated in outbred albino rat experiments. Oral correction with slightly alkaline sodium hydrocarbonate solution reduced the destructive effect of the urine on rat colorectal mucosa.
