title: Vestibular loss disrupts daily rhythm in rats.
abstract: Hypergravity disrupts the circadian regulation of temperature (Temp) and locomotor activity (Act) mediated through the vestibular otolithic system in mice. In contrast, we do not know whether the anatomical structures associated with vestibular input are crucial for circadian rhythm regulation at 1 G on Earth. In the present study we observed the effects of bilateral vestibular loss (BVL) on the daily rhythms of Temp and Act in semipigmented rats. Our model of vestibular lesion allowed for selective peripheral hair cell degeneration without any other damage. Rats with BVL exhibited a disruption in their daily rhythms (Temp and Act), which were replaced by a main ultradian period (τ <20 h) for 115.8 ± 68.6 h after vestibular lesion compared with rats in the control group. Daily rhythms of Temp and Act in rats with BVL recovered within 1 wk, probably counterbalanced by photic and other nonphotic time cues. No correlation was found between Temp and Act daily rhythms after vestibular lesion in rats with BVL, suggesting a direct influence of vestibular input on the suprachiasmatic nucleus. Our findings support the hypothesis that the vestibular system has an influence on daily rhythm homeostasis in semipigmented rats on Earth, and raise the question of whether daily rhythms might be altered due to vestibular pathology in humans.
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France; tristan.martin61@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Martin
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France;
authors.forename: B
authors.initials: B
authors.lastname: Mauvieux
authors.affiliation: LMNO, Université de Caen, CNRS UMR 6139, Caen Cedex, France; and Department of Mathematics, University of Bergen, Bergen, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Bulla
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France;
authors.forename: G
authors.initials: G
authors.lastname: Quarck
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France;
authors.forename: D
authors.initials: D
authors.lastname: Davenne
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France; CHU de Caen, Service des Explorations Fonctionnelles, Caen, France;
authors.forename: P
authors.initials: P
authors.lastname: Denise
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France;
authors.forename: B
authors.initials: B
authors.lastname: Philoxène
authors.affiliation: UNICAEN, COMETE, Caen, France; INSERM, U1075, Caen, France; Normandie Université, France;
authors.forename: S
authors.initials: S
authors.lastname: Besnard
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D018471:Hypergravity; D008297:Male; D009043:Motor Activity / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D014722:Vestibule, Labyrinth / Q000502:physiology*
keywords: biological rhythms; locomotor activity; rats; temperature; vestibular system