Inhaled Ethanol Induces Conditioned Preference And Aversion In Infant Rats.

PAUTASSI RM; NIZHNIKOV M; MOLINA J.C.,; SPEAR, LP

Washington, DC, USA

Congreso; 31a Reunión Científica Anual de la Research Society on Alcoholism (RSA); 2008

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-MX; mso-fareast-language:ES-MX;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> Inhalation of ethanol induces teratology in the developing rat and drug dependency in adults. However, little is known about the acute motivational effects of inhaled ethanol. Three experiments assessed hedonic effect of ethanol inhalation in infant rats when the drug was presented in a continuous conditioning trial or in separate, distributed trials. Maximum blood ethanol concentrations induced by the latter drug-delivery schedules were approximately 55 and 15 mg%, respectively (Experiment 1).  In Exp. 2 and 3, daily conditioning sessions were conducted on postnatal days 14 and 15. In Experiment 2, subjects were exposed to a tactile conditioned stimulus (CS, sandpaper) either paired or unpaired with ethanol vapor. A tactile preference test revealed a significant aversion for the CS in pups given continuous exposure to ethanol vapor. In Experiment 3, a pre-exposure phase involving brief exposure to ethanol vapor or uncontaminated air preceded tactile-ethanol pairings. During conditioning, pups were given distributed pairings between the tactile CS and ethanol or uncontaminated air. A tactile preference test indicated that ethanol-preexposed animals spent significantly more time on the ethanol-related CS relative to time spent on an alternative texture. These results indicate that, in infant rats, inhaled ethanol exerts differential hedonic effects as a function of schedule of exposure and ethanol pre-exposure treatments. Continuous experience with ethanol vapor induces aversive learning, seemingly driven by the orosensory effects of the drug. Yet, a brief pre-exposure to ethanol vapor allowed later expression of ethanol-mediated appetitive learning in pups given distributed conditioning trials.