MYOCARDIAL CAPILLARY DENSITY IN HYPERTENSIVE RATS

  • 1 January 1982
    • journal article
    • research article
    • Vol. 46  (1) , 54-60
Abstract
The density of myocardial capillaries was determined in spontaneous hypertensive (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats. Standard procedures were used to determine the systolic blood pressure of the animals. Specimens for light microscopic studies were sampled from the middle portion of the left ventricular free wall of in situ K+-arrested, glutaraldehyde-fixed hearts. The heart weight of SHR rats did not reveal significant hypertrophy as compared to WKY rats, despite the high systolic blood pressure recorded in the SHR. The mean capillary density was 18,514 .+-. 341 in SHR and 18,128 .+-. 362 in WKY. Transmural gradient was apparent in the left ventricular free wall of both animal groups. The capillary density declined with age in both SHR and WKY. The myocardium of both normotensive and hypertensive rats contains a high capillary density per mm2. Apparently, the number of capillaries per unit area is unchanged in spontaneous hypertension, and pressure overload of modest magnitude does not induce detectable myocardial hypertrophy.