title: Differential arousal regulation by prokineticin 2 signaling in the nocturnal mouse and the diurnal monkey.
abstract: The temporal organization of activity/rest or sleep/wake rhythms for mammals is regulated by the interaction of light/dark cycle and circadian clocks. The neural and molecular mechanisms that confine the active phase to either day or night period for the diurnal and the nocturnal mammals are unclear. Here we report that prokineticin 2, previously shown as a circadian clock output molecule, is expressed in the intrinsically photosensitive retinal ganglion cells, and the expression of prokineticin 2 in the intrinsically photosensitive retinal ganglion cells is oscillatory in a clock-dependent manner. We further show that the prokineticin 2 signaling is required for the activity and arousal suppression by light in the mouse. Between the nocturnal mouse and the diurnal monkey, a signaling receptor for prokineticin 2 is differentially expressed in the retinorecipient suprachiasmatic nucleus and the superior colliculus, brain projection targets of the intrinsically photosensitive retinal ganglion cells. Blockade with a selective antagonist reveals the respectively inhibitory and stimulatory effect of prokineticin 2 signaling on the arousal levels for the nocturnal mouse and the diurnal monkey. Thus, the mammalian diurnality or nocturnality is likely determined by the differential signaling of prokineticin 2 from the intrinsically photosensitive retinal ganglion cells onto their retinorecipient brain targets.
authors.affiliation: Department of Pharmacology, University of California, Irvine, CA, USA. qzhou@uci.edu.
authors.forename: Qun-Yong
authors.initials: QY
authors.lastname: Zhou
authors.affiliation: Department of Pharmacology, University of California, Irvine, CA, USA.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Burton
authors.affiliation: Department of Biomedical Sciences, Iowa State University, Ames, IA, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Neal
authors.affiliation: Department of Neurosurgery, Kunming Medical University Hospital, Yunan, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Qiao
authors.affiliation: Department of Biomedical Sciences, Iowa State University, Ames, IA, USA.
authors.forename: Anumantha G
authors.initials: AG
authors.lastname: Kanthasamy
authors.affiliation: Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Xu
authors.affiliation: Institute of Primate Translational Medicine, Kunming University of Science and Technology, Yunnan, China.
authors.forename: Yuanye
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Pharmacology, University of California, Irvine, CA, USA.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D001143:Arousal / Q000528:radiation effects; D001683:Biological Clocks / Q000528:radiation effects; D002940:Circadian Rhythm / Q000528:radiation effects; D005768:Gastrointestinal Hormones / Q000378:metabolism*; D000882:Haplorhini; D008027:Light; D051379:Mice; D008954:Models, Biological; D009043:Motor Activity / Q000528:radiation effects; D009479:Neuropeptides / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000528:radiation effects; D017299:Rod Opsins / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects; D013997:Time Factors; D000099210:Melanopsin
chemical_list: D005768:Gastrointestinal Hormones; D009479:Neuropeptides; D017299:Rod Opsins; D000099210:Melanopsin; C486586:Prok2 protein, mouse
keywords: Circadian clock output; Diurnal; Intrinsically photosensitive retinal ganglion cells; Nocturnal; Oscillation; Prokineticin 2; Sleep; Superior colliculus; Suprachiasmatic nucleus; Wakefulness