ARTERIAL HYPERTENSION AND CARDIAC HYPERTROPHY EMPHASYZING THE EXPERIMENTAL USE OF NITRIC OXIDE SYNTHESIS BUFFER: A BRIEF SURVEY

Abstract

The hypertension is a frequent disorder in modern industrial countries. In men, the arterial hypertension has been identified as one of the most important risk factors in cardiovascular diseases. In Brazil, the first causes of mortality are the cardiovascular diseases, representing about 30.8% of the total deaths. A study conducted over 30 years in Framingham, Massachusetts, has convincingly demonstrated that arterial hypertension is the most important etiologic factor associated with the appearance of symptomatic heart failure, being left ventricular hypertrophy the major risk factor. The ventricular hypertrophy is also associated with various forms of arrhythmias and is a risk factor of cardiac sudden death. The tachycardia and ventricular fibrillation are lethal arrhythmias and were estimated to cause approximately 400,000 deaths per year in the United States, but the knowledge of the mechanisms involving the ventricular arrhythmias in patients with cardiomyopathy is still weak. The nitric oxide (NO) is an endothelium vasorelaxing factor and is related with at least few cases of arterial hypertension in humans. The L-Name, N^w-nitro-Arginine-methyl-ester (analog and antagonist of the aminoacid L-Arginine, from which the NO is produced), interrupt the NO synthesis necessary to maintenance the normal arterial pressure. The cardiomyopathies are composed of a group of deseases, with frequently unknown etiology, in which the involvement of the cardiac muscle is the dominant characteristic. The classification of the World Health Organization is the most utilized to classify the cardiomiopathies. In this classification the term cardiomyopathy is restricted to the muscular cardiac desease of unknown origin. The hypertension induced by the use of L-Name may be an experimental model to be utilized in the study of the cardiomyopathy but further studies must be carried on to identify the similarity of events that occur during this hypertension and compare them to the cardiomyopathies. The aim of this brief review is to summarize some researches, including that produced in our laboratory, related to the arterial hypertension in experimental animals with emphasis on L-Name model.