title: The circadian system of Trypanosoma cruzi-infected mice.
abstract: The effects of Chagas disease on the mammalian circadian system were studied in Trypanosoma cruzi-infected C57-B16J mice. Animals were inoculated with CAI or RA strains of T. cruzi or vehicle, parasitism confirmed by blood specimen visualization and locomotor activity rhythms analyzed by wheel-running recording. RA-strain infected mice exhibited significantly decreased amplitude of circadian rhythms, both under light-dark and constant dark conditions, probably due to motor deficiencies. CAI-treated animals showed normal locomotor activity rhythms. However, in these mice, reentrainment to a 6h phase shift of the LD cycle took significantly longer than controls, and application of 15min light pulses in DD produced smaller phase delays of the rhythms. All groups exhibited light-induced Fos expression in the suprachiasmatic nuclei. We conclude that the main effect of T. cruzi infection on the circadian system is an impairment of the motor output from the clock toward controlled rhythms, together with an effect on circadian visual sensitivity.
authors.affiliation: Weill Medical College of Cornell University, New York, New York, USA
authors.forename: Tomás
authors.initials: T
authors.lastname: Fernández Alfonso
authors.forename: Ana María
authors.initials: AM
authors.lastname: Celentano
authors.forename: Stella Maris
authors.initials: SM
authors.lastname: Gonzalez Cappa
authors.forename: Diego A
authors.initials: DA
authors.lastname: Golombek
mesh_terms: D000204:Activity Cycles / Q000502:physiology; D000818:Animals; D014355:Chagas Disease / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000502:physiology; D017440:Photoperiod; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000378:metabolism