Changes In Ethanol’s Motivational Effects As A Function of The Development Of The Toxic Process

PAUTASSI RM; SANDERS S; TRUXELL E; MILLER S; SPEAR, N.E.; MOLINA J.C.,

Vancouver, Canada

Congreso; 27a Reunión Científica Anual de la Research Society on Alcoholism; 2004

Research Society on Alcoholism

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES-AR; mso-fareast-language:ES-AR;} @page Section1 {size:8.5in 11.0in; margin:70.85pt 85.05pt 70.85pt 85.05pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> CHANGES IN ETHANOL’S MOTIVATIONAL EFFECTS AS A FUNCTION             OF THE DEVELOPMENT OF THE TOXIC PROCESS.   R.M. Pautassi, S. Sanders, E. Truxell, S. Miller, N. E. Spear & J.C. Molina Instituto Ferreyra, Córdoba, Argentina, Facultad de Psicología, UNC  & Dept. of Psychology, Binghamton University, NY.                In infant rats, the strength of an associative memory not only depends on the contiguity between a conditioned and an unconditioned stimulus (CS and US, respectively) but also on the integrity of the US. Reevaluations (deflations or inflations) in the magnitude of the original memory may arise from postconditioning manipulations of the US representation. The goal of the following set of experiments was to evaluate whether ethanol’s capability to reevaluate an aversive memory changes during the course of the toxic episode. A first experiment indicated that four conditioning trials, defined by the explicit pairing between a salient odor cue (lemon, CS) and the infusion of a sapid solution (citric acid, US) were optimal in terms of generating a strong aversive conditioned response in 14 day-old pups. As measured in a two-way odor preference test, those animals that experienced paired presentations of the CS and US (paired group) spent significantly less time over lemon when compared with control pups that had been exposed to both stimuli in an unpaired fashion. In a second experiment, citric acid mediated-aversive conditioning was followed by re-exposure to citric acid 5 or 25 min after being intragastrically administered with a 2.5 g/kg EtOH dose (reevaluation phase). Olfactory preference tests were then conducted. A mixed ANOVA indicated that paired animals showed an aversion to the lemon odor that lasted throughout the test. This aversion was significantly higher in those animals that, during the reevaluation phase, experienced citric acid 25 min after being administered with the 2.5g/kg EtOH dose. These results indicate that ethanol’s capability to reevaluate an aversive memory changes as a function of the development of the toxic episode. This evidence adds to prior work (Pautassi et al, 2002) suggesting that, early in ontogeny, ethanol exerts differential hedonic effects during the course of the intoxication. The sensitivity of the unconditional stimulus reevaluation paradigm here utilized suggests that this procedure stands as a valid alternative to evaluate ethanol’s aversive hedonic properties.