Human chagasic IgG and muscarinic cholinergic receptor interaction: pharmacological and molecular evidence

GOIN, J.C.; PÉREZ LEIRÓS, C.; BORDA, E.; STERIN-BORDA, L.

MOLECULAR NEUROPHARMACOLOGY

Macmillan Press Ltd.

Lugar: London; Año: 1994 vol. 3 p. 189 - 196

0959-5244

1. The interaction of IgG from Trypanosoma cruzi infected patients with cardiac cholinergic receptors was characterized. 2. Chagasic IgG caused a concentration-dependent inhibition (in a non-competitive manner) of the binding of [3H]-quinuclidinyl benzylate to the cardiac membranes and a concentration-dependent immunoprecipitation of muscarinic acetylcholine receptors solubilized from cardiac membranes. 3. By means of SDS-PAGE and immunoblotting analysis, chagasic sera recognized a band of aproximately 80 kDa. The electrophoretic analysis of prelabelled immunoprecipitated proteins revealed a peak of [3H]-propylbenzilylcholine mustard (PBCM) with apparent molecular weight similar to that of the muscarinic acetylcholine receptor, and which dissapeared in the presence of atropine. 4. Chagasic IgG triggered biological effects associated with cholinergic-mediated cellular transmembrane signals (i.e. stimulation of cGMP, inhibition of cAMP, and a decrease of atrial contractility. 5. The implications of these results in the pathogenesis of the cardiac dysautonomia described in Chagas´ disease are discussed.