title: Fos induction in the amygdala by vestibular information during hypergravity stimulation.
abstract: Altered gravity environments including both hypo- and hypergravity can elicit motion sickness. Vestibular information is known to be essential for motion sickness, but its other neural substrates are poorly understood. We previously showed that bilateral lesions of the amygdala suppressed hypergravity-induced motion sickness in rats, using pica behavior as an emetic index. We show in the present study that during hypergravity stimulation, vestibular information activated the central nucleus of the amygdala (CeA), as determined by the induction of Fos expression, in comparison between normal and bilaterally labyrinthectomized rats. The finding that Fos expression was confined to the CeA and almost completely absent in other subnuclei of the amygdala contrasted with many previous studies that used other stressful stimuli such as foot shock, restraint and forced swimming, suggesting a specific vestibular effects on the amygdala. Prolongation of hypergravity resulted in reduction of Fos expression in the CeA, suggesting a process of habituation. Such decreases appeared earlier than in the vestibular nucleus, suggesting that adaptive changes in the CeA to hypergravity were independent of changes in the vestibular input. Our results suggest the amygdala is a neural substrate involved in the development of and habituation to motion sickness.
authors.affiliation: Department of Otolaryngology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.forename: Arata
authors.initials: A
authors.lastname: Horii
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kawamoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Uno
authors.forename: Munehisa
authors.initials: M
authors.lastname: Fukushima
authors.forename: Suetaka
authors.initials: S
authors.lastname: Nishiike
authors.forename: Noriaki
authors.initials: N
authors.lastname: Takeda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000679:Amygdala / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D003714:Denervation; D006185:Habituation, Psychophysiologic / Q000502:physiology; D018471:Hypergravity / Q000009:adverse effects*; D007150:Immunohistochemistry; D008297:Male; D009041:Motion Sickness / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D016761:Oncogene Proteins v-fos / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014726:Vestibular Nuclei / Q000502:physiology; D014722:Vestibule, Labyrinth / Q000502:physiology*
chemical_list: D016761:Oncogene Proteins v-fos