Noradrenaline, atrial natriuretic peptide, bombesin and neurotensin in myocardium and blood of rats in congestive cardiac failure

Abstract

Rats given monocrotaline develop severe right ventricular hypertrophy often accompanied by ascites and pleural effusions. In rats with right ventricular hypertrophy and no serous effusions ("hypertrophy" group), ventricular concentrations of noradrenaline were reduced but ventricular contents were unchanged. Atrial concentrations of noradrenaline were unaffected. Those with more severe right ventricular hypertrophy and serous effusions ("failure" group) had greatly reduced concentrations of noradrenaline in all four chambers, particularly on the right side; the right and left ventricular contents of noradrenaline were also diminished. The distributions of ir-ANP, ir-bombesin and ir-neurotensin in the normal rat heart are presented. ANP concentration fell to 33% in the right atrium and 46% in the left atrium of "failure" animals and to 57% in the right atrium of "hypertrophy" animals. Right ventricular content of ANP, normally low, increased more than two-fold in both groups, the concentration remaining unchanged. Left ventricular content of ANP decreased in the "failure" group. Concentrations of bombesin and neurotensin fell in both ventricles of both groups. Ventricular contents of bombesin did not change, but ventricular contents of neurotensin decreased, especially on the right side. Plasma ANP rose nearly six-fold while plasma bombesin and neurotensin fell in the "failure" group. Plasma peptide concentrations were unchanged in the "hypertrophy" group. The studies show the utility of the monocrotaline model in distinguishing between the effects of hypertrophy and those associated specifically with the syndrome of congestive cardiac failure.