Alterations in geometry and structure of coronary arteries have
marked consequences on blood flow to the respective area. We
evaluated long-term effect of losartan on blood pressure (BP),
heart weight/body weight (HW/BW), geometry and structure of
septal branch of coronary artery (RS) of young SHR and Wistar
rats. Four-week-old Wistar rats and SHR were used. Losartan
was administered (20 mg/kg/day) in drinking water by gavage
for 5 weeks. BP was measured by plethysmographic method.
Cardiovascular system was perfused with a fixative (120 mm Hg).
RS was processed for electron microscopy. Wall thickness of
intima + media (WT), inner diameter (ID), cross-sectional area of
intima + media (CSA), volume densities (VD) of endothelial cells
(EC), extracellular matrix (ECM) of intima, smooth muscle cells
(SMC) and ECM of media were evaluated. BP of 4-week-old SHR
did not differ from that of Wistar rats. BP, HW/BW, WT, CSA,
WT/ID, CSAs of SMC, ECM of media were increased in 9-weekold SHR, whereas their VD and CSA of EC were decreased.
Losartan administration decreased BP and HW/BW in both
groups. Geometry of RS was affected only in SHR (reduction of
WT, CSA, WT/ID and increased of ID, circumferential tension, VD
and CSA of EC). Losartan administration reduced BP and
myocardial mass in both groups and beneficially affected
geometry and structure of coronary artery in SHR.
Lack of Long-Term Effect of Vitamin C Supplementation on Blood Pressure