Long-term effect of losartan administration on blood pressure, heart and structure of coronary artery of young spontaneously hypertensive rats.
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-week-old 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.
Koprdova
R
R
Institute of Normal and Pathological Physiology and Center of Excellence for Cardiovascular Research, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Cebova
M
M
Kristek
F
F
D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects*; D006332:Cardiomegaly / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D003331:Coronary Vessels / Q000187:drug effects* / Q000648:ultrastructure; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D006321:Heart / Q000187:drug effects*; D006973:Hypertension / Q000150:complications / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D019808:Losartan / Q000008:administration & dosage*; D009206:Myocardium / Q000473:pathology; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D017539:Tunica Intima / Q000187:drug effects / Q000648:ultrastructure; D017540:Tunica Media / Q000187:drug effects / Q000648:ultrastructure
D047228:Angiotensin II Type 1 Receptor Blockers; D000959:Antihypertensive Agents; D019808:Losartan