RESUMO
The atrial natriuretic peptide (ANP) is a peptide hormone that is mainly produced in the cardiac atria, where it is stored within granules. It is known that the four regions of the atrial-auricular complex (two atria and two auricles) produce and store ANP in the granules. However, no report has been presented comparing the presence of ANP, and the number and diameter of atrial granules in the atria and auricles. ANP immunoreactivity was detected in cardiocytes from the four regions of the atrial-auricular complex. No differences were observed among the regions. The number of granules was greatest in the right atrium followed by the left atrium and left auricle and right auricle, in this order. The diameter of granules in the cardiocytes was significantly largest in the right atrium and reduced via the left auricle to the left atrium and right auricle. Both the number and diameter of the granules are larger in the right atrium in comparison with the other regions of the atrial-auricular complex, which leads to the supposition that this region is the one that most synthesizes and stores the ANP.
Assuntos
Fator Natriurético Atrial/análise , Átrios do Coração/citologia , Miócitos Cardíacos/citologia , Animais , Função do Átrio Direito , Fator Natriurético Atrial/metabolismo , Feminino , Lateralidade Funcional , Cobaias , Átrios do Coração/ultraestrutura , Imuno-Histoquímica , Masculino , Microscopia Eletrônica , Miócitos Cardíacos/ultraestruturaRESUMO
OBJECTIVE: To carry out a quantitative assessment in human myocardium cells of senile individuals, in right, left and septal ventricular regions. METHODS: Five hearts from corpses of individuals without heart diseases, of both sexes, with age between 67 and 87 years old were used. The following parameters were assessed: myocyte unit cross section area (myoc. a(o)); myocyte unit perimeter length (myoc. l(o)); myocyte unit volume (myoc. v(o)); myocyte volumetric density (myoc. V(v)); number of myocytes per volume unit (Nmm 3myoc.). The t-test of Student was used in statistic analysis. RESULTS: The analysis of differences (p < 0.05) among right (RV), left (LV) and septal (S) ventricular regions of human heart showed that myoc. a(o) values were lower in RV (1.51 +/- 0.10 microm2) and in S (1.55 +/- 0.07 microm2) in relation to LV (1.84 +/- 0.24 microm2). Values of myoc. l(o) were also shown lower in S (5.11 +/- 0.46 microm) comparing to LV (6.2 +/- 0.97 microm). Likewise, myoc. v(o) and myoc. V(v) showed lower values in RV (88.75 +/- 25.37 microm3; 0.39 +/- 0.03%) in relation to LV (122.41 +/- 16.31 microm3; 0.41 +/- 0.01%). CONCLUSION: Results obtained show that there may be changes in dimensions of left ventricular wall myocyte cell during senescent stage. However, those differences are subtle and seem to mean the adjustment of tissue to functional changes that install along life.