Motivational Properties Of Ethanol In Preweanling Rats Assessed By Means Of A Novel Operant Learning Task.

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

Atlanta, GA, USA

Congreso; 39th Annual Meeting International Society for Developmental Psychobiology; 2006

International Society for Developmental Psychobiology

<!-- /* 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; mso-fareast-language:ES;} @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;} --> While several studies have shown that newborn rats are highly sensitive to ethanol (EtOH) appetitive properties, it has been difficult to obtain such evidence in older infants, in part due to the lack of age-specific operant learning tasks. Our aim was to asssess EtOH motivational properties in preweanlings rats by means of a novel operant technique. On postnatal day 13 (PD13) Sprague-dawley rats were stimulated with intraoral water or alcohol (7%, 2 trials of 15 min, 5ul/min; preexposure phase). During PDs 14 to 16 (training phase), pups were individually introduced in plexiglas boxes. A dime-sized disk equipped with a touch-sensitive chip was placed in one corner. Pups received an intraoral infusion of ethanol (3 or 5%, 5 ul) after each contact with the sensor. Daily trials lasted for 20 min; yoked controls were employed for each experimental condition. On PD17 sensor touching was recorded but no reinforcer was available (extinction phase). Regardless preexposure condition and drug concentration, experimental pups made significantly more target behavior than controls on PD 14, an effect likely to reflect appetitive properties of EtOH. This result was significantly enhanced after partitioning the whole sample of subjects in two groups (high- and low responders) using median number of responses as the criterion. A general decrease in sensor touching was observed across PD’s 15-17, an effect that was greater for experimental animals during PD 16. Decreases in EtOH intake after animals achieved maximum self-administration levels were also observed, suggesting the development of conditioned avoidance to ingested ethanol.