Effects of pre- and postnatal ethanol exposure upon maternal behavior and infantile ultrasonic vocalizations

CULLERÉ, M.E.; MARCH, S. M.; SPEAR, N. E.; MOLINA, J. C.

Congreso; 2010 Scientific Meeting of the Research Society on Alcoholism. RSA, EEUU, 2010; 2010

Research Society on Alcoholism

Ethanol administration during late pregnancy and/or lactation modifies the dynamic of thedam/pup dyad. Ultrasonic vocalizations (USV) are considered an anxiety-related response.Moreover, these responses can be modulated through a variety of factors, such as: socialisolation, warmth, odours, maternal behavior and milk letdown. Infant rats emit more USVs ifthey have previously interacted with an alcohol-intoxicated dam, than pups reared by watertreateddams (Molina et al 2000). The present study analyzed maternal behavior and pupsemittedUSVs as a function of alcohol exposure. Pregnant rats received 0 or 2 g/kg ethanolduring gestational days 17 to 20. At PD 3, dams were administered with 0 or 2.5 g/kgethanol. Fifteen minutes later, dams were allowed to interact with their offspring, and maternalretrieval and crouching latencies were registered. One hour later, dams were removed fromthe nest and USVs were assessed under the presence of different odors (no odor, ethanol,and vanilla). Statistical analysis showed that alcohol intoxication during lactation disruptedmaternal behaviors such as pup retrieval and crouching. This effect was not observed whendams had prior ethanol experience during late pregnancy. These results confirm prior datarelative to maternal development of ethanol tolerance that modulates the interaction with itsoffspring. When USVs were analyzed, a significant interaction between pre- and postnataltreatment was also found independently from odor stimulation. Pups that had never beenexposed to ethanol showed very low levels of USVs. Pre- or postnatal exposure to ethanolresulted in heightened distress calls. The maximum level of USVs was found in pups thatexperienced ethanol in utero and during lactation. In other words, pups that experienced thedrug during late gestation and breastfeeding were particularly reactive to a novel environmentwhile isolated. Late prenatal ethanol exposure might be sufficient to induce hyperreactivityunder stressful conditions. This level of responsiveness seems to further increase wheninteracting with an intoxicated dam. Hence, it is possible that, despite the apparentdevelopment of maternal ethanol tolerance, other maternal behaviors or physiologicalalterations (e.g., hypothermia, milk let down) are detected by the infant. In accordance withthis hypothesis, sequential ethanol exposure may lead to enhanced infantile sensitivity tomoderate stressful events such as social isolation.