Morphometric study of early postnatal development in the left and right ventricular myocardium of the rat. II. Tissue composition, capillary growth, and sarcoplasmic alterations.
- 1 April 1980
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation Research
- Vol. 46 (4), 503-512
- https://doi.org/10.1161/01.res.46.4.503
Abstract
The absolute and differential growths of the capillary network and of myocyte cytoplasmic components in the left (L) and right (R) ventricular free walls were measured morphometrically from 1-5 days and from 5-11 days after birth. From 1-11 days, capillary length, luminal volume, luminal surface area and endothelial cell volume each increased 2-3 times more rapidly than myocardial mass or myocyte mass in each ventricle. Mean intercapillary distance and the transverse cross sectional area of the average capillary decreased markedly. The mean number of capillaries across the ventricular walls increased from 16 to 79 (L) and 14 to 22 (R). Maturation of the cytoplasm of left and right ventricular myocytes from 1-11 days included increases in the volume percentage of myofibrils (1.2-fold), mitochondria (1.8-fold) and smooth endoplasmic reticulum (2.1-fold) and increases in mean mitochondrial size [1.9-fold (L), 1.2-fold (R)] and number per cell [2.7-fold (L), 3.6-fold (R)]. Despite a 2-fold greater overall left ventricular growth the myocardial compositions of both ventricles were nearly indistinguishable at 1 and 11 days. Subcellular and microvascular changes were generally achieved more rapidly in the left ventricle from 1-5 days of age, demonstrating many structural differences and a lagging development in the right ventricle at 5 days. Postnatal myocardial adaptation to the altered work demands on the left and right ventricles shortly after birth resulted in morphological changes that could be the basis for a transient disparity in ventricular functions at about 5 days of age.This publication has 28 references indexed in Scilit:
- The predominance of binucleation in isolated rat heart myocytesJournal of Anatomy, 1977
- Calcium accumulating and ATPase activity of cardiac sarcoplasmic reticulum before and after birthCardiovascular Research, 1977
- Ultrastructural changes in rabbit heart mitochondria during the perinatal periodDevelopmental Biology, 1977
- Intercapillary distances and capillary reserve in right and left ventricles: Significance for control of tissue pO2Microvascular Research, 1976
- Brief Reviews : Determination of Left Ventricular Size and ShapeCirculation Research, 1974
- Regulation of myocardial function—A subcellular phenomenonJournal of Molecular and Cellular Cardiology, 1973
- Quantitative electron microscopic description of heart muscle cells: Application to normal, hypertrophied and thyroxin-stimulated heartsThe American Journal of Cardiology, 1973
- Ultrastructural basis of acute left ventricular failure from severe acute aortic stenosis in the rabbitJournal of Molecular and Cellular Cardiology, 1972
- Cardiovascular hemodynamics in the fetal lamb before and after lung expansionAmerican Journal of Physiology-Legacy Content, 1964