title: Effect of (L)-cysteine on acetaldehyde self-administration.
abstract: Acetaldehyde (ACD), the first metabolite of ethanol, has been implicated in several behavioural actions of alcohol, including its reinforcing effects. Recently, we reported that l-cysteine, a sequestrating agent of ACD, reduced oral ethanol self-administration and that ACD was orally self-administered. This study examined the effects of l-cysteine pre-treatment during the acquisition and maintenance phases of ACD (0.2%) self-administration as well as on the deprivation effect after ACD extinction and on a progressive ratio (PR) schedule of reinforcement. In a separate PR schedule of reinforcement, the effect of l-cysteine was assessed on the break-point produced by ethanol (10%). Furthermore, we tested the effect of l-cysteine on saccharin (0.2%) reinforcement. Wistar rats were trained to self-administer ACD by nose poking on a fixed ratio (FR1) schedule in 30-min daily sessions. Responses on an active nose-poke caused delivery of ACD solution, whereas responses on an inactive nose-poke had no consequences. l-cysteine reduced the acquisition (40 mg/kg), the maintenance and the deprivation effect (100 mg/kg) of ACD self-administration. Furthermore, at the same dose, l-cysteine (120 mg/kg) decreased both ACD and ethanol break point. In addition, l-cysteine was unable to suppress the different responses for saccharin, suggesting that its effect did not relate to an unspecific decrease in a general motivational state. Compared to saline, l-cysteine did not modify responses on inactive nose-pokes, suggesting an absence of a non-specific behavioural activation. Taken together, these results could support the hypotheses that ACD possesses reinforcing properties and l-cysteine reduces motivation to self-administer ACD.
authors.affiliation: Department of Drug Sciences, via Muroni 23, University of Sassari, 07100 Sassari, Italy. apeana@uniss.it
authors.forename: Alessandra T
authors.initials: AT
authors.lastname: Peana
authors.forename: Giulia
authors.initials: G
authors.lastname: Muggironi
authors.forename: Giulia R
authors.initials: GR
authors.lastname: Fois
authors.forename: Manuel
authors.initials: M
authors.lastname: Zinellu
authors.forename: Donatella
authors.initials: D
authors.lastname: Sirca
authors.forename: Marco
authors.initials: M
authors.lastname: Diana
mesh_terms: D000079:Acetaldehyde / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D003545:Cysteine / Q000494:pharmacology*; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012054:Reinforcement, Psychology; D012439:Saccharin / Q000494:pharmacology; D012646:Self Administration
chemical_list: D000431:Ethanol; D012439:Saccharin; D000079:Acetaldehyde; D003545:Cysteine