HEART AUTONOMIC INNERVATION DURING THE ACUTE-PHASE OF EXPERIMENTAL AMERICAN TRYPANOSOMIASIS IN THE DOG

Heart autonomic innervation was studied in dogs during the acute phase of the experimental infection with the Berenice-78 strain of Trypanos oma cruzi. A glyoxylic acid-induced fluorescence method for catecholam ines and a thiocholine method for demonstrating acetylcholinesterase a ctivity showed the sympathetic and the parasympathetic nerve fibers, r espectively. At day 34 of infection, moderate-to-intense rarefaction o f both cholinergic and noradrenergic nerve fibers occurred in the atri a of all animals coincident with moderate to intense myocarditis. In t he ventricles, sympathetic denervation was clearly present only when t he inflammatory processes were moderate to intense. Preliminary result s on the chronic phase indicate that normal autonomic innervation coex ists with an incipient chronic fibrosing myocarditis.