title: An in vitro circadian rhythm of protein synthesis in the rat suprachiasmatic nucleus under tissue culture conditions.
abstract: Because inhibitors of protein synthesis produce changes in the circadian rhythm of wheel-running activity in rodents, we examined the circadian changes of in vitro protein synthesis by the rat suprachiasmatic nucleus (SCN). We demonstrated a robust circadian rhythm of [14C]leucine incorporation as well as [3H]2-deoxyglucose (2DG) uptake by the SCN. The peak time of 2DG uptake was around circadian time 6-9 h (CT6-CT9). In contrast to 2DG uptake, the maximum rate of leucine incorporation occurred around CT22-CT0. Thus, the leucine incorporation rate preceded 2DG uptake by 6-9 h. Leucine incorporation was inhibited by protein synthesis inhibitors, but not by tetrodotoxin. Since a robust circadian rhythm of leucine incorporation by the SCN was detected in vitro by using our method, this procedure may be useful to study the circadian clock function of the SCN.
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shibata
authors.forename: T
authors.initials: T
authors.lastname: Hamada
authors.forename: K
authors.initials: K
authors.lastname: Tominaga
authors.forename: S
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001345:Autoradiography; D002940:Circadian Rhythm / Q000502:physiology*; D046508:Culture Techniques; D003513:Cycloheximide / Q000494:pharmacology; D007930:Leucine / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D016707:Tissue Fixation
chemical_list: D009419:Nerve Tissue Proteins; D013779:Tetrodotoxin; D003513:Cycloheximide; D007930:Leucine