title: Rhythmic expression of per1 in the dentate gyrus is suppressed by corticosterone: implications for neurogenesis.
abstract: The stimulating action of anti-depressant drugs on the number of mitotic cells on the dentate gyrus on the adult rat depends on an intact diurnal rhythm of corticosterone. This suggests that there may be a clock mechanism in the dentate gyrus which is sensitive to corticoids. This paper reports the diurnal expression the 'clock' gene per1 in the dentate gyrus, and how it is altered by clamping the diurnal rhythm in corticosterone. We show that there is a diurnal rhythm in the number of mitotic progenitor cells in the dentate gyrus of the hippocampus in adult male per1-luciferase rats, approximately 6 h out of phase with the plasma corticosterone rhythm. This is suppressed by clamping the daily corticosterone levels by a subcutaneous implant of corticosterone (100 mg). There was also a daily rhythm of per1 expression in both suprachiasmatic nucleus (SCN) and the dentate gyrus, which were in phase with one another. The per1 rhythm in the dentate gyrus, but not the SCN, was suppressed by clamping the plasma corticosterone rhythm. These results are related to the previous finding that clamping the corticosterone rhythm also prevents the stimulating action of fluoxetine and other controlling agents on the mitotic activity of the progenitor cells.
authors.affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gilhooley
authors.forename: S B
authors.initials: SB
authors.lastname: Pinnock
authors.forename: J
authors.initials: J
authors.lastname: Herbert
mesh_terms: D000818:Animals; D002452:Cell Count / Q000379:methods; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D003345:Corticosterone / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D018891:Dentate Gyrus / Q000187:drug effects / Q000378:metabolism*; D004343:Drug Implants; D008297:Male; D055495:Neurogenesis / Q000187:drug effects / Q000502:physiology*; D056950:Period Circadian Proteins / Q000378:metabolism*; D051381:Rats; D055647:Rats, Transgenic; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000378:metabolism
chemical_list: D004343:Drug Implants; C539024:Per1 protein, rat; D056950:Period Circadian Proteins; D003345:Corticosterone