title: [The role of melatonin receptor and GABAA receptor in the sleeping time prolonged by melatonin in mice].
abstract: OBJECTIVE
  To observe the role of melatonin receptor and GABAA receptor in sleeping time prolonged by melatonin in mice.
  
  
  METHODS
  The absence of the righting reflex was considered as the sleep onset and the duration of the loss of the righting reflex was recorded as the sleeping time. The effects of receptor agonist and antagonist on hypnotic activity of melatonin were studied in the paper.
  
  
  RESULTS
  Prazosin hydrochloride, the blocker of melatonin 3 receptor, didn't affect the sleeping time prolonged by melatonin in mice. GABA, the endogenous agonist of GABA receptor, significantly potentiated the hypnotic activity of melatonin. When picrotoxin, the ligand of picrotoxin site on GABAA receptor, used together with melatonin, it significantly antagonized the sleeping time prolonged by melatonin, however, bicuculline, the specific antagonist of GABA binding site in GABAA receptor, didn't affect the hypnotic activity of melatonin in mice.
  
  
  CONCLUSIONS
  Melatonin does not exhibit its potentiation sleeping time in mice through melatonin 3 receptor. Hypnotic activity of melatonin may be mediated through picrotoxin site on GABAA receptor.
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang 110016, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Dan
authors.initials: D
authors.lastname: Zou
authors.forename: Jing-Cai
authors.initials: JC
authors.lastname: Li
authors.forename: Chi
authors.initials: C
authors.lastname: Hong
authors.forename: Li-Bin
authors.initials: LB
authors.lastname: Chen
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D008297:Male; D008550:Melatonin / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D010852:Picrotoxin / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000502:physiology*; D044094:Receptors, Melatonin / Q000502:physiology*; D012890:Sleep / Q000502:physiology*
chemical_list: D001640:Bicuculline; D008550:Melatonin; D010852:Picrotoxin; D011224:Prazosin; D011963:Receptors, GABA-A; D044094:Receptors, Melatonin