Sera from chronic chagasic patients depress cardiac electrogenesis and conduction
Braz. j. med. biol. res
;
33(4): 439-46, Apr. 2000.
Article
in English
| LILACS
| ID: lil-258179
ABSTRACT
We report results obtained with sera from 58 chronic chagasic patients that were evaluated for effects on heart rate and atrioventricular (AV) conduction in isolated rabbit hearts and screened for the presence of muscarinic and beta-adrenergic activity. We show that sera from 26 patients decreased heart rate, while 10 increased it and 22 had no effect. Additionally, sera from 20 of the 58 patients blocked AV conduction. Muscarinic activation seems to be involved in both effects, but is not the only mechanism, since atropine did not antagonize the decrease in heart rate in 23 percent of sera or AV block in 40 percent. Sera from patients with complex arrhythmias were significantly more effective in depressing both heart rate and AV conduction. Sera that induce increases in heart rate seem to operate exclusively through beta-adrenergic activation. Two of these sera, evaluated with respect to intercellular communication in primary cultures of embryonic cardiomyocytes were able to block gap junction conductance evaluated by a dye injection technique after 24-h exposure. The mechanisms underlying this uncoupling effect are currently being investigated
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Receptors, Muscarinic
/
Chagas Disease
/
Cholinergic Agents
Limits:
Animals
/
Humans
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2000
Type:
Article
/
Congress and conference
Affiliation country:
Brazil
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