PREGANGLIONIC FIBERS OF THE ADRENAL-MEDULLA AND CERVICAL SYMPATHETIC-GANGLIA - DIFFERENTIAL INVOLVEMENT DURING EXPERIMENTAL AMERICAN TRYPANOSOMIASIS IN RATS
Ers. Camargos et al., PREGANGLIONIC FIBERS OF THE ADRENAL-MEDULLA AND CERVICAL SYMPATHETIC-GANGLIA - DIFFERENTIAL INVOLVEMENT DURING EXPERIMENTAL AMERICAN TRYPANOSOMIASIS IN RATS, International journal of experimental pathology, 77(3), 1996, pp. 115-124
The acute phase of experimental Chagas' disease in rats is associated
with early lesions of the post-ganglionic sympathetic nerve terminals
of the heart, the varicosities being the target. In the superior cervi
cal and stellate ganglia the preganglionic fibres showed no signs of l
esion in the course of experimental Chagas' disease. In the adrenal me
dulla, however, the acute phase of the Trypanosoma cruzi infection ind
uced a clear rarefaction of the acetylcholinesterase-positive nerve fi
bres (20 and 32 days after infection). Recovery of the normal pattern
occurred in most animals by day 125 after infection. At days 20, 32 an
d 46 after infection, electron-microscopic studies demonstrated the oc
currence of damage in cholinergic nerve terminals contacting the chrom
affin cells. The signs of damage included dense bodies, clumps of syna
ptic vesicles and filaments, rarefaction of all organelles, vacuoles a
nd irregular contour. The ultrastructural peculiarities of the sympath
etic ganglia may explain the ganglionar microenvironment protective ag
ainst the hazardous factors elicited by acute Chagas' disease.