Effects of losartan on haemodynamic parameters and angiotensin receptor mRNA levels in rat heart after myocardial infarction

• Main Authors: Yi Zhun Zhu, Yi-Chun Zhu, Jun Li, Heiner Schäfer, Wolfgang Schmidt, Tai Yao, Thomas Unger
• Format: Article
• Language: English
• Published: Hindawi - SAGE Publishing 2000-09-01
• Series: Journal of the Renin-Angiotensin-Aldosterone System
• Online Access: https://doi.org/10.3317/jraas.2000.039

We investigated the haemodynamic parameters and the regulation of cardiac mRNA levels of the angiotensin receptor subtypes, AT 1 and AT 2 , by the AT 1 -receptor antagonist losartan in rat heart during the acute phase of myocardial infarction. AT 1 - and AT 2 -receptor mRNA levels markedly increased at 30 minutes and peaked at 24 hours post myocardial infarction (12.6-fold increase for AT 1 - and 17.2-fold increase for AT 2 compared with controls). Losartan significantly reduced mean blood pressure in sham-operated rats and decreased mean blood pressure and left ventricular end-diastolic pressure in myocardial infarction rats. However, the AT 1 - and AT 2 -receptor mRNA levels of losartan-treated rats showed a pattern similar to that of water-treated rats. The time-dependent increase of AT 1 - and AT 2 receptor mRNA levels is associated with the early remodelling process of non-infarcted myocardium post MI and is independent of AT 1 -receptor blockade.