Effects of alcohol and lorazepam during extinction of alcohol self-administration in rats

Jackson, Anne, Duka, Theodora and Stephens, David N (2003) Effects of alcohol and lorazepam during extinction of alcohol self-administration in rats. Journal of Psychopharmacology, 17 (3). pp. 293-299. ISSN 0269-8811

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Systemic injections of alcohol have previously been reported to ‘prime’ or to reinstate self-administration of
alcohol in rats, and it has been suggested that the priming effects of drugs are related to their stimulus
properties. We tested this hypothesis by investigating the effects of lorazepam, which cross-generalizes with
alcohol in animal drug-discrimination studies, in rats trained to self-administer 7% alcohol in an operant
paradigm. Once animals were trained, extinction tests were carried out twice weekly, before which rats were
injected with either vehicle, alcohol (0.063–0.5 g/kg, i.p.) or lorazepam (0.03–0.25 mg/kg, i.p.). Alcohol did not
increase responding for alcohol during extinction. Doses of 0.25 and 0.5 g/kg reduced alcohol-appropriate lever
pressing (p < 0.05 versus 0 g/kg), with the largest dose also suppressing general activity (p < 0.02 versus 0 g/kg).
Lorazepam also reduced alcohol-appropriate responding, in a behaviourally specific manner; doses of 0.03
mg/kg and above decreased lever pressing (p < 0.05 versus 0 mg/kg), whereas general activity was depressed at
0.06 mg/kg and larger doses (p < 0.05 versus 0 mg/kg). Although lorazepam mimicked the effect of alcohol at
doses predicted to do so on the basis of their relative potency in drug discrimination studies, neither alcohol
nor lorazepam primed rats to respond for alcohol. By contrast, the pattern of results suggested that, in this
model, they ‘satiated’ or substituted for alcohol, resulting in a reduced motivation to respond.

Item Type: Article
Keywords: alcohol lorazepam rats relapse self-administration stimulus properties
Schools and Departments: School of Psychology > Psychology
Depositing User: Dora Duka
Date Deposited: 06 Feb 2012 15:35
Last Modified: 28 Feb 2013 15:00
URI: http://sro.sussex.ac.uk/id/eprint/13367
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