Abstract
Groups of young rats were kept in a hypoxic chamber or in air as control animals for 28 days. Hypoxic and control animals were treated with .alpha.-methyl-3,4-dihydroxyphenylalanine (.alpha.-methyldopa) or distilled water. .alpha.-Methyldopa significantly reduced increase in pulmonary artery pressure and right ventricular hypertrophy induced by chronic hypoxia and partially prevented histological changes in small pulmonary vessels.