Histamine synthesis inhibition reduces light-induced phase shifts of circadian rhythms.
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.
Eaton
S J
SJ
Department of Psychology, Smith College, Northampton, MA 01063, USA.
Cote
N K
NK
Harrington
M E
ME
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
D004791:Enzyme Inhibitors; D006633:Histamine Antagonists; D008762:Methylhistidines; C028309:alpha-fluoromethylhistidine; D006632:Histamine; D006640:Histidine Decarboxylase