Can CS devaluation and extinction memory recollection prevent the reinstatement of drug-seeking behavior?

• Grant number: 06/00262-1
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2006
• End date: November 30, 2008
• Field of knowledge: Humanities - Psychology - Experimental Psychology
• Principal Investigator: Silvio Morato de Carvalho
• Grantee: Silvio Morato de Carvalho
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

This study aims to develop preclinical procedures able to attenuate or prevent the drug-seeking behavior reinstatement. Rats will be trained to self-administrate drugs by pressing a bar in a Skinner box. Each time rat presses the active lever; a pair of events (sound/light) will be on during 6 seconds. 3 seconds after light/sound were on, an infusion pump will be activated by 6 seconds, and drugs (cocaine or amphetamine) or sucrose will be delivered. Drugs will be delivered right in the jugular vein, and sucrose in the magazine. After bar presses be stable, rats' bar press behavior will be put on extinction schedule. In this phase, a third of rats from each group (cocaine, amphetamine and sucrose) will be exposed to an intermittent and high sound. The purpose of this environmental change is to produce an extinction memory. After extinction phase has ended, and 5 hours before reinstatement tests begin, another third of rats from those three groups will receive a lithium chloride injection. Under effects of lithium, rats will be left in Skinner box during 30 min in presence of cue events (sound/light). The purpose of this pairing of stimuli (lithium effects and sound/light cues) is to devaluate the power of conditioned stimulus in anticipating drugs infusion or sucrose delivering. Another third of rats will no be exposed to any environmental change during the extinction phase or before the reinstatement tests. 30 min before reinstatement tests begin, half of rats from each group will be given an (i.p.) injection of either cocaine or amphetamine or access to 2 ml of sucrose. The other half will not exposed to any procedure right before reinstatement tests begin. During reinstatement tests, bar press behavior on active lever will be followed by sound/light, cue events. When these events will be on, none consequence will be delivered as bar press behavior occurs. It is expected that devaluation of conditioned events and extinction memory be procedures useful to attenuate or prevent drug-seeking behavior reinstatement. (AU)