title: Histamine synthesis inhibition reduces light-induced phase shifts of circadian rhythms.
abstract: Circadian rhythms are generated by the hypothalamic suprachiasmatic nuclei, a site of dense histaminergic innervation. Histamine can phase shift circadian rhythms in a manner similar to light. In this experiment, we administered alpha-fluoromethylhistidine (FMH), an inhibitor of histamine synthesis, prior to a light pulse in hamsters housed under constant darkness. Photic phase shifts in wheel-running rhythms were significantly attenuated by FMH pretreatment. These results suggest that histamine may modulate photic input to the circadian clock.
authors.affiliation: Department of Psychology, Smith College, Northampton, MA 01063, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Eaton
authors.forename: N K
authors.initials: NK
authors.lastname: Cote
authors.forename: M E
authors.initials: ME
authors.lastname: Harrington
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D006224:Cricetinae; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006632:Histamine / Q000096:biosynthesis*; D006633:Histamine Antagonists / Q000494:pharmacology*; D006640:Histidine Decarboxylase / Q000037:antagonists & inhibitors; D008297:Male; D008647:Mesocricetus; D008762:Methylhistidines / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D010775:Photic Stimulation; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; D006633:Histamine Antagonists; D008762:Methylhistidines; C028309:alpha-fluoromethylhistidine; D006632:Histamine; D006640:Histidine Decarboxylase