ENHANCED ALCOHOL INTAKE AFTER ALCOHOL FETAL EXPOSURE IN THE RAT: THE ROLE OF THE OPIOID SYSTEM

CHOTRO, M. G.; ARIAS, C.; LECLERQU, I

San sebastian, Espana

Congreso; Sociedad Espanhola de psicologia comparada, SEPC.; 2001

Previous studies have shown that the administration of a moderate alcohol dose during gestational days 17-20 in the rat results in an enhanced alcohol consumption by the offspring, when tested on preweanling stages. During this last gestational period the rat fetus can perceive taste and odors present in the amniotic fluid, can show basic forms of associative and non associative learning and its opioid system is functional. Considering that biochemical and behavioral data indicate that opiate antagonists may reduce reinforcing properties of alcohol, it was hypothesized that the effect of increased alcohol intake after prenatal ethanol exposure could obey to a conditioned preference resulting from the association between sensory and reinforcing properties of alcohol mediated by the opioid system. To test this hypothesis a series of experiments was assessed. On the first one, pregnant rats received through gestational days 17-20 one daily intragastric administration of either a 2 g/kg ethanol dose (E) or water (W) immediately followed by subcutaneous injection of Naloxone (Nal) or saline (Sal). On postnatal day 14 all pups were tested in their consumption of either an alcohol solution or water. Results show that infants prenatally exposed to only alcohol (E-Sal) consumed significantly more alcohol than pups from group W-Sal. Subjects from group E-Nal, however, did not show this increased ethanol intake in comparison to W-Nal treated pups or to any of the remaining two groups. In a second experiment, it was discarded the possibility that the effect could be the result of a sensitization of the opioid system as a consequence of its prenatal stimulation, using an agonist of m receptors (DAMGO). A third experiment was run with the idea of extinguishing the prenatal association. These results seem to support the hypothesis of a conditioned preference response established in utero after maternal alcohol administration.