title: L-cysteine, a thiol amino acid, increases the stimulating acute effect of ethanol on locomotion.
abstract: The present study deals with the effect of L-cysteine on the acute stimulating effects of ethanol. Swiss albino mice were pretreated with 0.0, 18.75, 37.50, or 75.00 mg/kg of cysteine simultaneously, 30 or 60 min, before the administration of saline or 0.8, 1.6, 2.4, or 3.2 g/kg of ethanol at 20% vol./vol. After these treatments, mice were left in the open-field chamber for 20 min, and locomotor activity was evaluated for the last 10 min. The specificity of the effects of L-cysteine was analyzed with the use of two drugs that also induce locomotor activity--d-amphetamine and methanol. Mice received L-cysteine (37.5 mg/kg), and 30 min after this treatment d-amphetamine (2 mg/kg) or methanol (2.4 g/kg) was injected. Data showed that L-cysteine at 37.5 mg/kg was able to increase locomotion induced by 2.4 and 3.2 g/kg of ethanol when it was administered 30 min before ethanol injection. The effects of L-cysteine are specific for the stimulation of ethanol on locomotion, because L-cysteine does not alter d-amphetamine-induced locomotor activity or methanol-induced locomotion. Moreover, blood ethanol levels were not affected by L-cysteine pretreatment. Therefore, the present findings demonstrated that ethanol-induced locomotor effects are enhanced by L-cysteine, in a manner similar to that of other sulfur amino acids.
authors.affiliation: Area de Psicobiología, Universidad de Jaén, 23071 Jaén, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Escarabajal
authors.forename: M
authors.initials: M
authors.lastname: Miquel
authors.forename: C M
authors.initials: CM
authors.lastname: Aragon
mesh_terms: D000818:Animals; D002492:Central Nervous System Depressants / Q000008:administration & dosage* / Q000097:blood; D003545:Cysteine / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D000431:Ethanol / Q000008:administration & dosage* / Q000097:blood; D007274:Injections, Intraperitoneal; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051379:Mice; D013438:Sulfhydryl Compounds / Q000494:pharmacology
chemical_list: D002492:Central Nervous System Depressants; D013438:Sulfhydryl Compounds; D000431:Ethanol; D003545:Cysteine