Table 4

Changes in atrial rate and cAMP production by antipeptide chagasic autoantibodies

AdditionsAtrial rate (beats/min)cAMP
(pmol/mg wet wt)
None (control)143 (11)3.8 (0.3)
Antipeptide IgG95 (4)4-150 0.9 (0.1)4-150
Antipeptide IgG + peptide138 (9)3.1 (0.3)
Antipeptide IgG + atropine145 (10)3.7 (0.5)
Antipeptide IgG + AF-DX 116140 (9)3.4 (0.4)
Antipeptide IgG + pertussis toxin142 (8)2.9 (0.3)
Normal IgG146 (10)3.6 (0.2)
Carbachol93 (8)4-150 0.7 (0.1)4-150
  • Values are mean (SEM) and represent the effect of 12 chagasic antipeptide IgG experiments from patients in group IA. Results show the maximum effects on frequency of contraction and cAMP production by antipeptide IgG (1 × 10−8 M) compared with normal IgG (5 × 10−7 M) and carbachol (5 × 10−7 M). Inhibition studies were performed by incubating rat atria either with peptide, atropine, AF-DX 116 (5 × 10−7 M), or pertussis toxin (1 μg/ml).

  • 4-150 Significantly different from control, p < 0.001.