title: Circadian rhythm of histamine release from the hypothalamus of freely moving rats.
abstract: Using an in vivo microdialysis technique coupled with HPLC-fluorometry, the release of neuronal histamine from the anterior hypothalamic area was monitored continuously in conscious, freely moving rats under a 12:12 h light:dark cycle. Spontaneous locomotor activity of the rats was measured simultaneously using a locomotor activity counter. Histamine release gradually increased in the second half of the light period (1400-2000) and the average histamine release during the dark period (2000-0800, 0.20 +/- 0.02 pmol/30 min) was significantly higher than that during the light period (0.12 +/- 0.01 pmol/30 min). This clear circadian change in the release suggests that the central histaminergic system is related to the circadian rhythm of rats.
authors.affiliation: Department of Pharmacology II, Faculty of Medicine, Osaka University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mochizuki
authors.forename: A
authors.initials: A
authors.lastname: Yamatodani
authors.forename: K
authors.initials: K
authors.lastname: Okakura
authors.forename: A
authors.initials: A
authors.lastname: Horii
authors.forename: N
authors.initials: N
authors.lastname: Inagaki
authors.forename: H
authors.initials: H
authors.lastname: Wada
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D006632:Histamine / Q000378:metabolism*; D007032:Hypothalamus, Anterior / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D006632:Histamine