Operant coditioning in neonate rats as a function of an ethanol-mediated associative fetal memory.

S.M. MARCH; P. ABATE; O.B. HAYMAL; N.E. SPEAR; J.C. MOLINA

Baltimore, Washington

Congreso; 2006 Scientific Meeting of the Research Society on Alcoholism; 2006

Research Society on Alcoholism

During the last days of gestation, fetal rats are able to detect sensory and toxic ethanol (EtOH) properties, and to retain information related to its effects. Prenatal experiences with the drug, through maternal intoxication, lead to an increase in alcohol response latter in life. A fetal conditioning procedure in which an aromatic cue (cineole) is associated with maternal-fetal intoxication with a moderate dose of EtOH has been developed. In this study we aimed to evaluate operant conditioning in neonatal rats as a function of prenatal associative experiences with the drug. We wanted to assess if neonates exposed to EtOH prenatally, are able to acquire an operant response and, if prenatal learning related to the drug could modulate operant conditioning when cues related to this memory are presented. Three prenatal treatments were conducted during gestational days (GDs) 17 -20 and were defined as follows: Paired group, dams received an i.g. administration of cineole followed 15 min. later by a 2.0 g/kg EtOH dose; Long-delay group, dams received cineole 6 hours before ethanol intoxication; Water group, dams received two administrations of water separated by 15 min. On PD1 neonates were trained in an operant task. When they pushed a touch sensitive key, they received an infusion of milk, or milk contaminated with cineole directly into theirs mouths. Control subjects received both substances, but unrelated to their behavior (yoked subjects). Training session lasted 15 min. After one hour, extinction session begun. Frequency of pushing the sensitive key was recorded. In spite of not haven found an interaction between prenatal treatment, neonatal solution and learning condition (paired or yoked) during the acquisition trial, we were able to observe it during extinction procedure. Pertinent ANOVA shows that neonates prenatally exposed to cineole paired with EtOH keep pressing the key touch, if they had been trained using cineole in milk. This study evidenced that operant conditioning in neonate rats, is a useful tool for evaluating prenatal learning related to EtOH’s effects. Additionally, ethanol-related prenatal memories modulate operant responsiveness when pups are re-exposed to the cue that predicted toxic consequences of the drug.