Endogenous dopamine regulates the rhythm of expression of the clock protein PER2 in the rat dorsal striatum via daily activation of D2 dopamine receptors.
A role for dopamine (DA) in the regulation of clock genes in the mammalian brain is suggested by evidence that manipulations of DA receptors can alter the expression of some clock genes outside the suprachiasmatic nucleus (SCN), the master circadian clock. The role of endogenous DA in the regulation of clock gene expression is unknown. Here, we demonstrate a direct relationship between extracellular DA levels and the rhythm of expression of the clock protein PERIOD2 (PER2) in the dorsal striatum of the male Wistar rat. Specifically, we show that the peak of the daily rhythm of extracellular DA in the dorsal striatum precedes the peak of PER2 by ∼6 h and that depletion of striatal DA by 6-hydroxydopamine or α-methyl-para-tyrosine or blockade of D(2) DA receptors by raclopride blunts the rhythm of striatal PER2. Furthermore, timed daily activation of D(2) DA receptors, but not D(1) DA receptors, restores and entrains the PER2 rhythm in the DA-depleted striatum. None of these manipulations had any effect on the PER2 rhythm in the SCN. Our findings are consistent with the idea that the rhythm of expression of PER2 in the dorsal striatum depends on daily dopaminergic activation of D(2) DA receptors. These observations may have implications for circadian abnormalities seen in Parkinson's disease.
Center for Studies in Behavioral Neurobiology/Groupe de Recherche en Neurobiologie Comportementale, Department of Psychology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
Suzanne
S
Hood
Pamela
P
Cassidy
Marie-Pierre
MP
Cossette
Yuval
Y
Weigl
Michael
M
Verwey
Barry
B
Robinson
Jane
J
Stewart
Shimon
S
Amir
D000818:Animals; D002452:Cell Count; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000166:cytology / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D065127:Dopamine D2 Receptor Antagonists; D005786:Gene Expression Regulation / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D008474:Medial Forebrain Bundle / Q000502:physiology; D017551:Microdialysis; D009043:Motor Activity / Q000502:physiology; D016627:Oxidopamine; D056950:Period Circadian Proteins / Q000096:biosynthesis* / Q000235:genetics*; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000378:metabolism; D013563:Sympathectomy, Chemical; D013565:Sympatholytics; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors
D065127:Dopamine D2 Receptor Antagonists; C513311:Per2 protein, rat; D056950:Period Circadian Proteins; D017448:Receptors, Dopamine D2; D013565:Sympatholytics; D012313:RNA; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine