Acute sensitivity and acute tolerance to ethanol in preweanling rats with or without prenatal experience with the drug

ARIAS C; MLEWSKY, C; PAUTASSI RM; MOLINA J.C.,; SPEAR, N.E.

PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR

Elsevier

Año: 2008 vol. 89 p. 608 - 622

0091-3057

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES-MX; mso-fareast-language:ES-MX;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> Exposure to moderate ethanol doses during late gestation in the rat results in subsequent heightened affinity for ethanol ingestion. This treatment also appears to sensitize neonates to ethanol’s acute effects of the drug. The present study examined the effect of prenatal ethanol exposure on infantile behavioral sensitivity to different ethanol doses known to exert biphasic motivational effects (appetitive and aversive). The design of the experiment was conceived not only to assess acute behavioral sensitivity to ethanol but also to analyze the development of acute tolerance, the impact of pre- and postnatal ethanol administration upon habituation processes and the possible interaction between these phenomena. 13-day old pups derived from 27 Sprague-Dawley dams were employed. During gestational days 17-20 dams received a daily intragastric (i.g.) administration of 0.0 or 2.0 g/kg ethanol. At postnatal days 13 pups were given ethanol (0.0, 0.5 or 2.5 g/kg, i.g.) and later assessed in terms of locomotor activity. One third of the pups were evaluated at three post-administration times: 5-10, 30-35 and 60-65 min. Another third was tested only during the last two post-administration periods while the remaining subjects were only tested at post-administration time 60-65 min. Regardless of prenatal exposure, at 30-35 min blood ethanol levels reached similar values to those attained at 60-65 min (0.5 g/kg dose: 50 and 33 mg%, 2.5 g/kg dose: 125 and 200 mg%; respectively).  It was found that: a) Pups prenatally treated with ethanol exhibited heightened locomotor activity levels, b) Behavioral habituation was observed both within and between sessions. This process was not affected by prenatal treatment. c) The 2.5 g/kg ethanol dose induced biphasic effects (i.e., stimulation 5-10 post-administration; sedation at 30-35 or 60-65 minutes.) d) Independent of prenatal treatment, infants exhibited acute tolerance to ethanol’s sedative effectsThese results indicate that a moderate ethanol exposure during late pregnancy is sufficient to induce hyper-reactivity during infancy. This moderate prenatal ethanol exposure did not affect non-associative learning capabilities or acute sensitivity and tolerance to ethanol doses that exert biphasic locomotive effects.