Abstract
We investigated the involvement of calmodulin and Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the photic entrainment of circadian rhythms using calmodulin inhibitors such as calmidazolium (CMZ) and trifluoperazine (TFP), and a CaMKII inhibitor, KN-62, in rats. Fos expression in the suprachiasmatic nucleus (SCN) of rats induced by photic stimulation (300 lux, 1 h) during the early subjective night of the rats was inhibited by treatment with CMZ (10 mg/kg i.p.) or TFP (20 mg/kg i.p.) 30 min before photic stimulation. With respect to the neuronal firing rate in the rat SCN slice, KN-62 and CMZ application during the early subjective night attenuated the glutamate (10 microM)-induced phase shift. The present results suggest that calmodulin and CaMKII are involved in the photic entrainment mechanism in the rodent SCN.
MeSH terms
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / analogs & derivatives
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / pharmacology
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Analysis of Variance
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Animals
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Biomarkers
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Calcium-Calmodulin-Dependent Protein Kinase Type 2
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Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
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Calcium-Calmodulin-Dependent Protein Kinases / physiology*
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Calmodulin / antagonists & inhibitors
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Calmodulin / physiology*
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Circadian Rhythm / physiology*
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Drug Evaluation, Preclinical
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Enzyme Inhibitors / pharmacology*
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Imidazoles / pharmacology
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In Vitro Techniques
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Nerve Tissue Proteins / analysis
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Proto-Oncogene Proteins c-fos / analysis
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Rats
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Rats, Wistar
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Suprachiasmatic Nucleus / enzymology
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Suprachiasmatic Nucleus / physiology*
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Trifluoperazine / pharmacology
Substances
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Biomarkers
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Calmodulin
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Enzyme Inhibitors
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Imidazoles
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Nerve Tissue Proteins
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Proto-Oncogene Proteins c-fos
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Trifluoperazine
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calmidazolium
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KN 62
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
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Calcium-Calmodulin-Dependent Protein Kinase Type 2
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Calcium-Calmodulin-Dependent Protein Kinases