Acute Alcohol Produces Ataxia and Cognitive Impairments in Aged Animals: A Comparison Between Young Adult and Aged Rats

Background Aging in both humans and rodents appears to be accompanied by physiological changes that increase biologic sensitivity to ethanol ( E t OH ) intoxication. However, animal models designed to investigate this increased alcohol sensitivity have yet to be established. For this reason, we sought to determine whether acute E t OH administration produces differential effects on motor coordination and spatial cognition in young adult and aged rats. Methods Male young adult (postnatal day 70 to 72) and aged (~18 months) S prague‐ D awley rats were assessed on 2 motor tasks (the accelerating rotarod [ RR ] and the aerial righting reflex [ ARR ]) and a single cognitive performance task (the M orris water maze [ MWM ]). Following acute E t OH exposure via intraperitoneal injection, animals' performance was reassessed. Results Aged rats showed a dramatic increase in E t OH ‐induced ataxia on the RR and the ARR relative to young adult animals. Similarly, results from the MWM revealed that aged animals had slightly greater E t OH ‐induced impairments compared with young adult animals. Importantly, the increased impairments produced by E t OH were not due to differential blood E t OH levels. Conclusions We demonstrate for the first time that aged rats show greater E t OH ‐induced deficits compared with young adults in tasks of motor and cognitive performance. The possible role of protein kinase C as a mechanism for increased sensitivity to the motor‐impairing effects of E t OH is discussed. Given the high prevalence of alcohol use among the elderly, increased vulnerability to alcohol‐induced deficits may have a profound effect on injury in this population.