Differential Effects of Ethanol in Adolescent and Adult Rats

Abstract

Alcohol use in children and adolescents is widespread. However, very little is known about the effects of alcohol exposure during this period of postnatal development. The goal of the present study was to compare the relative sensitivity to the sedative effects of alcohol in periadolescent and adult rats. After treatment with either 4 or 5 g/kg ethanol, both 20- and 30-day-old rats regained their righting reflex significantly earlier than 60-day old rats. In 30-day-old rats, serum ethanol concentrations (SECs) were significantly greater at the time of the recovery of the righting reflex than 60-day-old rats. Developmental differences in the effects of ethanol on locomotor activity were also observed. In 60-day-old rats, 2.5 g/kg ethanol generally decreased locomotor activity. Ethanol did not significantly alter locomotor activity in 20- and 30-day-old rats. Finally there were significant developmental differences in the pharmacokinetics of ethanol with a significant delay in the time to peak SECs in 60-day-old rats relative to 20- and 30-day-old rats. These findings indicate that peri-adolescent rats are less sensitive to the sedative effects of ethanol as they recovered their righting reflex earlier and at significantly higher SECs than adult rats.

Adaptive plasticity of NMDA receptors and dendritic spines: Implications for enhanced vulnerability of the adolescent brain to alcohol addiction

“…This is also consistent with a number of studies indicating the hippocampus is particularly sensitive to the disruptive effects of ethanol. In contrast to the enhanced sensitivity to the cognitive impairing actions of ethanol, adolescent rats show reduced sensitivity to the sedative and motor impairing actions of acute ethanol (Little, et al, 1996;Silveri and Spear, 1998). In contrast, while acute ethanol induces greater levels of motor in-coordination in the adolescent brain, there is enhanced tolerance to an acute challenge of ethanol following prolonged exposure (Swartwelder, et al, 1998).…”

Oxytocin prevents ethanol actions at δ subunit-containing GABA A receptors and attenuates ethanol-induced motor impairment in rats

“…Righting-reflex test. The righting-reflex test is a widely used assay of motor coordination and sedation (48). Rats were placed inside a tub with corncob bedding and were placed on their back by the experimenter.…”

Chronic tolerance to the social consequences of ethanol in adolescent and adult Sprague-Dawley rats

“…One of the potential contributors to heavy drinking during adolescence may be an age-related insensitivity to various adverse effects of ethanol that serve as cues to terminate drinking. For instance, relative to their adult counterparts, adolescent rats are less sensitive to ethanol-induced motor impairment [13,28,47], sedation [21,23,27], and "hangover"-associated anxiety [8,41].…”