title: The efficacy of sodium channel blockers to prevent phencyclidine-induced cognitive dysfunction in the rat: potential for novel treatments for schizophrenia.
abstract: Sodium channel inhibition is a well precedented mechanism used to treat epilepsy and other hyperexcitability disorders. The established sodium channel blocker and broad-spectrum anticonvulsant lamotrigine is also effective in the treatment of bipolar disorder and has been evaluated in patients with schizophrenia. Double-blind placebo-controlled clinical trials found that the drug has potential to reduce cognitive symptoms of the disorder. However, because of compound-related side-effects and the need for dose titration, a conclusive evaluation of the drug's efficacy in patients with schizophrenia has not been possible. (5R)-5-(4-{[(2-Fluorophenyl)methyl]oxy}phenyl)-l-prolinamide (GSK2) and (2R,5R)-2-(4-{[(2-fluorophenyl)methyl]oxy}phenyl)-7-methyl-1,7-diazaspiro[4.4]nonan-6-one (GSK3) are two new structurally diverse sodium channel blockers with potent anticonvulsant activity. In this series of studies in the rat, we compared the efficacy of the two new molecules to prevent a cognitive deficit induced by the N-methyl-d-aspartic acid receptor antagonist phencyclidine (PCP) in the reversal-learning paradigm in the rat. We also explored the effects of the drugs to prevent brain activation and neurochemical effects of PCP. We found that, like lamotrigine, both GSK2 and GSK3 were able to prevent the deficit in reversal learning produced by PCP, thus confirming their potential in the treatment of cognitive symptoms of schizophrenia. However, higher doses than those required for anticonvulsant efficacy of the drugs were needed for activity in the reversal-learning model, suggesting a lower therapeutic window relative to mechanism-dependent central side effects for this indication.
authors.affiliation: Neuroscience Centre of Excellence for Drug Discovery, Medicines Research Centre, GlaxoSmithKline SpA., Verona, Italy. charles.large@autifony.com
authors.forename: Charles H
authors.initials: CH
authors.lastname: Large
authors.forename: Silvia
authors.initials: S
authors.lastname: Bison
authors.forename: Ilaria
authors.initials: I
authors.lastname: Sartori
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Read
authors.forename: Alessandro
authors.initials: A
authors.lastname: Gozzi
authors.forename: Davide
authors.initials: D
authors.lastname: Quarta
authors.forename: Marinella
authors.initials: M
authors.lastname: Antolini
authors.forename: Emma
authors.initials: E
authors.lastname: Hollands
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Gill
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Gunthorpe
authors.forename: Nagi
authors.initials: N
authors.lastname: Idris
authors.forename: Jo C
authors.initials: JC
authors.lastname: Neill
authors.forename: Giuseppe S
authors.initials: GS
authors.lastname: Alvaro
mesh_terms: D000818:Animals; D003072:Cognition Disorders / Q000139:chemically induced* / Q000517:prevention & control*; D005260:Female; D008297:Male; D010622:Phencyclidine / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012193:Reversal Learning / Q000187:drug effects / Q000502:physiology; D012559:Schizophrenia / Q000139:chemically induced* / Q000517:prevention & control*; D026941:Sodium Channel Blockers / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D026941:Sodium Channel Blockers; D010622:Phencyclidine