title: Melatonin instantaneously resets intrinsic circadian rhythmicity in the rat suprachiasmatic nucleus.
abstract: In order to follow resetting of the rat circadian pacemaking system by melatonin in vivo, the rhythm in the light-induced c-fos expression was used as a marker of the intrinsic rhythmicity of the suprachiasmatic nucleus (SCN). A single melatonin administration during late day to rats maintained originally under a short photoperiod with 8 h of light per day or under a long photoperiod with 16 h of light per day phase advanced immediately the evening rise in the light-induced SCN c-Fos immunochemistry by about 1.5 h. The data indicate that melatonin administration in vivo may instantaneously reset the intrinsic SCN rhythmicity.
authors.affiliation: Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: A
authors.initials: A
authors.lastname: Sumová
authors.forename: H
authors.initials: H
authors.lastname: Illnerová
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D003624:Darkness; D007279:Injections, Subcutaneous; D008027:Light; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000276:immunology / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D008550:Melatonin