Orexin fibers form appositions with Fos expressing neuropeptide-Y cells in the grass rat intergeniculate leaflet.
Neuropeptide-Y (NPY) cells in the intergeniculate leaflet (IGL) are known to modulate effects of arousal on the mammalian circadian system. However, the route through which this information reaches the IGL has not been established. Here, we provide evidence that the orexins (hypocretins) are uniquely positioned as a potential source of activity state feedback to the IGL in the grass rat, Arvicanthis niloticus. Specifically, many NPY cells in the grass rat IGL exhibit orexin-A (OXA) fiber appositions. Furthermore, NPY cells contacted by OXA fibers are significantly more likely to express Fos during nocturnal wheel running than are NPY cells without such contacts (P < 0.001).
Nixon
Joshua P
JP
Department of Zoology, 203 Natural Science, Michigan State University, East Lansing, MI 48824-1115, USA. nixonjos@msu.edu
Smale
Laura
L
D000818:Animals; D002452:Cell Count / Q000379:methods; D005829:Geniculate Bodies / Q000166:cytology*; D007150:Immunohistochemistry / Q000379:methods; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D009412:Nerve Fibers / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D009478:Neuropeptide Y / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D016761:Oncogene Proteins v-fos / Q000378:metabolism*; D000068797:Orexins; D051381:Rats
D047908:Intracellular Signaling Peptides and Proteins; D009478:Neuropeptide Y; D009479:Neuropeptides; D016761:Oncogene Proteins v-fos; D000068797:Orexins