Regulation of basal rhythmicity in protein kinase C activity by melatonin in immortalized rat suprachiasmatic nucleus cells.
Melatonin phase shifts circadian rhythms of the neuronal firing rate and stimulates PKC activity at dusk (CT 10) and dawn (CT 23) in the rat suprachiasmatic nucleus (SCN) slice via activation of the MT(2) melatonin receptor. We demonstrated that in the SCN2.2 cells basal PKC activity follows a rhythmic oscillation with an acrophase during the subjective dark phase (CT 14-CT 22) and nadirs during the subjective light phase at CT 2 and CT 10. Melatonin (0.01-10 nM, 10 min) significantly doubled basal PKC activity at CT 2 and CT 10, and decreased basal PKC activity at CT 6. We conclude that melatonin regulates the basal rhythm in PKC activity generated in SCN2.2 cells at the same periods of sensitivity observed in the native SCN.
Rivera-Bermúdez
Moisés A
MA
Department of Molecular Pharmacology and Biological Chemistry, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Gerdin
Matthew J
MJ
Earnest
David J
DJ
Dubocovich
Margarita L
ML
D000818:Animals; D002461:Cell Line, Transformed; D002940:Circadian Rhythm / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D008550:Melatonin / Q000494:pharmacology*; D010507:Periodicity; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000201:enzymology*
D011493:Protein Kinase C; D008550:Melatonin