Biochemical indices of cholinergic and adrenergic autonomic innervation in dog heart: disparate alterations in chronic right heart failure.

D. D. LUND, P. G. SCHMID, U. J. JOHANNSEN AND R. ROSKOSK~, JR. Biochemical Indices of Cholinergic and Adrenergic Autonomic Innervation in Dog Heart: Disparate Alterations in Chronic Right Heart Failure. Journal of Molecular and Cellular Cardiology (1982) 14, 419-425. Abnormal reflex sympathetic and parasympathetic control of heart rate occurs in canine right heart failure. Therefore, we investigated the activities of enzymes catalyzing synthesis of acetylcholine (choline acetyltransferase) and norepinephrine (tyrosine hydroxylase and dopamine-P-hydroxylase) to assess possible mechanisms of altered parasympathetic and sympathetic function respectively in hearts of dogs with chronic (greater than 2 years) right heart failure produced by tricuspid avulsion and pulmonary artery constriction (n = 7) and sham animals (n = 7). In dogs with tricuspid avulsion and pulmonary artery constriction there was a reduction in sympathetic nemoenzymes in both the stressed right ventricle and non-stressed left ventricle without any alteration in the parasympathetic neuroenzymes in these regions. There were no detectable changes in any enzyme activities within the left atrium. In the right atrium, however, significant reductions occurred in both sympathetic and parasympathetic neurochemical indices in the region of the sinoatrial node. The variable pattern of cardiac sympathetic and parasympathetic changes in dogs with tricuspid avulsion and pulmonary artery constriction suggests the possibility of non-uniform alterations in autonomic neural control of the chronically diseased heart.