Trypanosomes cause dysregulation of c-fos expression in the rat suprachiasmatic nucleus.
Rats infected with the parasite Trypanosoma brucei brucei showed selective changes of c-fos expression in the suprachiasmatic nucleus of the hypothalamus (SCN) during spontaneous sleep (S) and wakefulness (W) under a basal 12 h/12 h light-dark (L-D) cycle. In the vast majority of W (D phase) control animals the SCN was devoid of cells displaying Fos-related immunopositivity, while Fos-like-immunoreactive (ir) neurones were detected in most S (L phase) control rats. In most infected animals, on the other hand, Fos-ir neurones were detected in the SCN during W, but not during the S period, with a significant difference between control and infected S rats. Thus, these data indicate that the basal c-fos expression in the SCN during the L-D and S-W cycles is considerably altered in experimental trypanosomiasis. This is the first observation of a selective change in the SCN in trypanosome-infected rat brains. Since the SCN plays an important role as a pace-maker for biological rhythms, this finding may provide a basis for understanding the pathogenesis behind endogenous rhythm dyregulation and changes in sleeping pattern in human trypanosomiasis (African sleeping sickness).
Bentivoglio
M
M
Institute of Anatomy, University of Verona, Italy.
Grassi-Zucconi
G
G
Peng
Z C
ZC
Bassetti
A
A
Edlund
C
C
Kristensson
K
K
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D004569:Electroencephalography; D005786:Gene Expression Regulation / Q000502:physiology*; D016762:Genes, fos / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012890:Sleep / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000378:metabolism* / Q000469:parasitology; D014353:Trypanosomiasis, African / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D014851:Wakefulness / Q000502:physiology