High Fos expression during the active phase in orexin neurons of a diurnal rodent, Tamias sibiricus barberi.
To investigate whether a diurnal animal possesses the orexinergic system implicating vigilance and behavior, we examined Fos immunoreactivity (IR) in orexinergic neurons of Korean chipmunks raised under 12h light-dark cycles. Brain tissue, collected at four different zeitgeber times (ZT), was double-labeled with Fos and orexin-A antibodies. There was no difference in the number of orexin-IR neurons in the hypothalamus across all ZTs. However, more orexin-IR neurons expressing Fos-IR were found at ZTs 3 and 9 than ZTs 15 and 21. The results demonstrate circadian variations in the activation of orexin neurons corresponding with locomotor cycles, similarly seen in nocturnal rodents.
Kodama
Tohru
T
Department of Psychology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526, Japan.
Usui
Setsuo
S
Honda
Yoshiko
Y
Kimura
Mayumi
M
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D016762:Genes, fos; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000502:physiology*; D007723:Korea; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009479:Neuropeptides / Q000032:analysis / Q000502:physiology*; D000068797:Orexins; D012589:Sciuridae / Q000502:physiology*; D013995:Time
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins