Early ethanol exposure and its effect on ethanol odor responses, consumption of ethanol and learning about ethanol's aversive properties

Exposure to large doses of ethanol during gestation results in morphological abnormalities as well as neuorbehavioral deficits. In addition to ethanol's teratogenic properties, which act upon the fetus in a rather passive manner, studies have also shown that fetuses are capable of learning about prenatal experiences with ethanol. The following chapters explore the nature of prenatal ethanol exposure and its effects on responding to ethanol odor, ethanol consumption, and on learning about ethanol. The first chapter uses a model of moderate prenatal ethanol exposure involving 2 g/kg of ethanol administered on the last four days of gestation. Rats were tested on postnatal day zero (P0, Exp 1.1) or P1 (Exp 1.3) for ethanol odor responding and on P14 for ethanol consumption (Exp 1.2, 1.3). Experiment 1.3 utilized a longitudinal design to test whether ethanol odor responding and ethanol intake were related. In the second chapter, a model of heavy prenatal ethanol exposure was used, which involved 5.25 g/kg of ethanol per day for six days starting on P4. Three days later, preweanlings were taught a conditioned taste aversion (CTA) to saccharin using either ethanol (Exp 2.1--2.3) or lithium chloride (LiCl, Exp 2.3) as the aversive agent. In chapter one, prenatal ethanol increased responsiveness to ethanol odor and led to heightened intake of the drug. Rats that had high levels of activity in a novel environment just prior to ethanol intake testing consumed more ethanol than those with low levels of activity. There was no relationship between ethanol odor responding soon after birth and ethanol consumption weeks later. In chapter two, neonatal treatment in general (sham or ethanol intubations) seemed to attenuate CTA learning using either a 2.0 g/kg dose of ethanol or LiCl. CTA learning using 2.5 g/kg ethanol as an aversive agent, however, was facilitated by neonatal ethanol exposure. Results in both chapters were amenable to discussion in terms of prenatal learning about ethanol regardless of whether a moderate or teratogenic dose was administered. These experiments contribute to our knowledge of early ethanol exposure and its effects on later responsiveness to the drug.