ACETALDEHYDE REINFORCEMENT AND MOTOR ACTIVITY IN NEWBORNS WITH OR WITHOUT A PRENATAL HISTORY OF ALCOHOL EXPOSURE.

MARCH, SM; CULLERÉ, ME; ABATE, P; HERNANDEZ JI; SPEAR, NE; MOLINA, JC

SAO PAULO

Congreso; 2011 Meeting of the Latin-American Society for Biomedical Research on Alcoholism (LASBRA). San Pablo, Brasil, March 31st-April 1st, 2011.; 2011

LATIN AMERICAN SOCIETY FOR BIOMEDICAL RESEARCH ON ALCOHOLISM

It has been observed that ethanol exposure during early development is associated with later acceptance of the drug. In humans, the development of alcohol related problems, such as abuse and dependence, is associated with prenatal and early exposure to the drug. In pre clinical studies we have observed that neonatal rats with a history of prenatal exposure to ethanol are more prone to self administer an ethanol solution than pups without such prior experience with the drug. Interestingly, this period of enhanced sensitivity to ethanol reinforcement is accompanied by a higher rate of activity in the central catalase system. The catalase system metabolizes ethanol in the brain. Acetaldehyde (ACD), the first oxidation product, has been found to share many ethanol-like effects. In the first experiment, we evaluated if a prenatal history of alcohol exposure (gestational days 17-20; 0.0 or 2.0 g/kg) modulated neonatal susceptibility to ACD‟s motor effects. ACD was centrally administered (0, 0.35 and 0.52 umol) and motor activity was registered. Latency to display motor activity was higher in neonates prenatally treated with water and challenged with the highest ACD dose relative to newborns receiving a similar ACD dose but with a positive prenatal ethanol history. In experiment 2, ACD‟s reinforcement was tested through an associative learning paradigm. ACD (0.35 umol) and ethanol (100 mg%) were selected as unconditioned stimuli (US) and centrally administered in contingency with lemon odor (conditioned stimulus, CS). Suckling response to an artificial nipple odorized with the CS was the dependent variable. Both USs supported appetitive conditioning in the neonatal rat independently for prenatal treatments. According to these results it appears that prenatal ethanol experience results in tolerance to ACD‟s motor activity effects. Additionally, appetitive conditioning was successfully achieved when ACD or EtOH were directly administered in the brain. The present results argue in favor of heightened sensitivity to EtOH's reinforcing effects within a stage in development where ACD production is probably higher than latter in life.