title: Sleep fragmentation, and changes in locomotor activity and body temperature in trypanosome-infected rats.
abstract: The rest-activity and body temperature 24 h cycles, as well as the structure of spontaneous sleep, were studied in rats 3 weeks after infection with monomorphic Trypanosoma brucei brucei. This parasite belongs to the species of trypanosomes that causes in humans African sleeping sickness, a neuropsychiatric syndrome that involves alterations of endogenous biological rhythms. In the infected rats, entrained to a 12 h:12 h photoperiod, a considerable hypokinesia was detected during the hours of darkness. A significant oscillation of the body temperature during 24 h was lost in some infected animals. In the other infected animals, the body temperature cycle displayed a lower amplitude and a phase advance. The mean temperature was slightly higher in the infected than in control rats during the period of light. A detailed analysis of the structure of spontaneous sleep, based on daytime electroencephalographic recordings, revealed during trypanosome infection an increased relative proportion of wake, and a decreased percent value of synchronized sleep. A marked reduction of the mean REM latency and a fragmented pattern of synchronized sleep, resulting in a considerable alteration of the REM-non-REM sleep sequences, were also observed in the infected animals. These findings indicate that trypanosomiasis in the rat results in a striking sleep fragmentation, as well as in changes of locomotor activity and body temperature rhythm. Thus, trypanosome infection in the rat provides an experimental model of sleep dysregulation in a structurally intact brain, and may provide an animal model of endogenous rhythm changes documented in African sleeping sickness.
authors.affiliation: Department of Cell Biology, University of Perugia, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Grassi-Zucconi
authors.forename: J A
authors.initials: JA
authors.lastname: Harris
authors.forename: A H
authors.initials: AH
authors.lastname: Mohammed
authors.forename: M V
authors.initials: MV
authors.lastname: Ambrosini
authors.forename: K
authors.initials: K
authors.lastname: Kristensson
authors.forename: M
authors.initials: M
authors.lastname: Bentivoglio
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D004569:Electroencephalography; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012893:Sleep Wake Disorders / Q000469:parasitology*; D014346:Trypanosoma brucei brucei; D014353:Trypanosomiasis, African / Q000503:physiopathology*