title: Effects of cholinergic system of dorsal hippocampus of rats on MK-801 induced anxiolytic-like behavior.
abstract: BACKGROUND
  Some investigations have shown that the glutamate receptors play a critical role in cognitive processes such as learning and anxiety.
  
  
  OBJECTIVE
  The possible involvement of the cholinergic system of the dorsal hippocampus in the anxiolytic-like response induced by MK-801, NMDA receptor antagonist, was investigated in the present study.
  
  
  METHODS
  Male Wistar rats were used in the elevated plus maze apparatus to test the parameters: open arm time (%OAT), open arm entries (%OAE), close arm time (%CAT), close arm entries (%CAE) and other exploratory behaviors (locomotor activity, grooming, rearing and defecation) of anxiety-like response.
  
  
  RESULTS
  The data indicated that intra-CA1 administration of MK-801 increased %OAT (2μg/rat) and %OAE (1 and 2μg/rat) while decreased %CAT and %CAE and did not alter other exploratory behaviors, indicating an anxiolytic-like effect. Moreover, intra-hippocampal injections of mecamylamine, a cholinergic receptor antagonists (2μg/rat) and scopolamine (4μg/rat), by themselves, 5min before testing, increased %OAT and %OAE but decreased %CAT and %CAE and did not alter locomotor activity and other exploratory behaviors, suggesting an anxiolytic-like effect. On the other hand, intra-CA1 co-administration of an ineffective dose of scopolamine (3μg/rat), but not mecamylamine (1μg/rat), with an ineffective dose of MK-801 (0.5μg/rat) increased %OAT and %OAE and decreased %CAT and %CAE. The data may indicate the possible involvement of the cholinergic system of the CA1 in the anxiolytic-like response induced by MK-801.
authors.affiliation: Department of Neuroscience, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@amss.ac.ir
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: Mohammad
authors.initials: M
authors.lastname: Nasehi
authors.forename: Morteza
authors.initials: M
authors.lastname: Piri
authors.forename: Negar
authors.initials: N
authors.lastname: Heidari
mesh_terms: D000109:Acetylcholine / Q000502:physiology*; D000818:Animals; D001008:Anxiety Disorders / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology*; D056547:CA1 Region, Hippocampal / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology*; D002799:Cholinergic Fibers / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016291:Dizocilpine Maleate; D000109:Acetylcholine