title: Differential cAMP gating of glutamatergic signaling regulates long-term state changes in the suprachiasmatic circadian clock.
abstract: We investigated a role for cAMP/protein kinase A (PKA) in light/glutamate (GLU)-stimulated state changes of the mammalian circadian clock in the suprachiasmatic nucleus (SCN). Nocturnal GLU treatment elevated [cAMP]; however, agonists of cAMP/PKA did not mimic the effects of light/GLU. Coincident activation of cAMP/PKA enhanced GLU-stimulated state changes in early night but blocked light/GLU-induced state changes in the late night, whereas inhibition of cAMP/PKA reversed these effects. These responses are distinct from those mediated by mitogen-activated protein kinase (MAPK). MAPK inhibitors attenuated both GLU-induced state changes. Although GLU induced mPer1 mRNA in both early and late night, inhibition of PKA blocked this event only in early night, suggesting that cellular mechanisms regulating mPer1 are gated by the suprachiasmatic circadian clock. These data support a diametric gating role for cAMP/PKA in light/GLU-induced SCN state changes: cAMP/PKA promotes the effects of light/GLU in early night, but opposes them in late night.
authors.affiliation: Department of Cell and Structural Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Tischkau
authors.forename: E A
authors.initials: EA
authors.lastname: Gallman
authors.forename: G F
authors.initials: GF
authors.lastname: Buchanan
authors.forename: M U
authors.initials: MU
authors.lastname: Gillette
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003624:Darkness; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D008027:Light; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D056950:Period Circadian Proteins; D010775:Photic Stimulation; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D011930:Reaction Time / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; C539024:Per1 protein, rat; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D018698:Glutamic Acid; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases