Evidence of the role of angiotensin AT(1) receptors in remote renal preconditioning of myocardium.

Abstract

The underlying mechanisms of myocardial preconditioning after a brief period of renal ischemia-reperfusion are unknown. The phenomenon itself and the involvement of AT(1) angiotensin receptors was therefore investigated using an in vivo rat model of acute myocardial infarction. Anesthetized rats underwent a left thoracotomy and pericardiotomy. A laparotomy was performed to expose the left renal artery. Animals were then preconditioned with four episodes, each consisting of 5 min of renal artery occlusion followed by 10 min of reperfusion, or underwent a 60 min sham period of anesthesia. Subsequently, the left coronary artery was occluded for 30 min and reperfused for 2 h. Area at risk and infarct size was estimated along with hemodynamic and temperature data recording. The infarct-to-risk ratio was limited from 56.36 +/- 2.36 and 50.65 +/- 4.71 in control to 12.0 +/- 0.48 and 12.57 +/- 0.44 in preconditioned hearts, by volume and weight methods. The protective effect of renal preconditioning on the myocardium was not abolished by losartan 1 mg/kg (10.11 +/- 0.12 and 11.2 +/- 1.4) pretreatment whereas it was completely attenuated by losartan 5 mg/kg (46.5 +/- 1.0 and 47.8 +/- 1.4) administration. Thus we can infer that angiotensin AT(1) receptors participate in renal preconditioning of the myocardium in in vivo rat hearts.

• Authors: D Singh, K Chopra
• Journal: Methods and findings in experimental and clinical pharmacology (Methods Find Exp Clin Pharmacol) Vol. 26 Issue 2 Pg. 117-22 (Mar 2004) ISSN: 0379-0355 [Print] Spain
• PMID: 15071610 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Receptor, Angiotensin, Type 1
• Angiotensin II
• Losartan

Topics

• Angiotensin II (metabolism, pharmacology)
• Animals
• Blood Pressure (drug effects)
• Body Temperature (physiology)
• Coronary Vessels (injuries)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Female
• Heart Rate (drug effects, physiology)
• Injections, Intravenous
• Ischemia (physiopathology)
• Ischemic Preconditioning, Myocardial (methods)
• Kidney (blood supply, injuries, physiopathology)
• Losartan (administration & dosage, pharmacology)
• Male
• Myocardial Infarction (physiopathology)
• Rats
• Rats, Wistar
• Receptor, Angiotensin, Type 1 (drug effects, physiology)
• Renal Artery (injuries)
• Reperfusion (methods)
• Time Factors