Intermittent binge alcohol exposure during the periadolescent period induces spatial working memory deficits in young adult rats

Abstract

Human and animal studies suggest adolescence is a period of heightened sensitivity to adverse cognitive sequelae of alcohol exposure. The current study assessed the effects of intermittent binge ethanol intoxication during the periadolescent period of Wistar rats on subsequent performance in a Morris water maze spatial navigation task. For 4 weeks (P32-56), rats were exposed to ethanol or air 3 days/week via vapor inhalation chambers. Acquisition of spatial navigation was assessed beginning 5 days after the final day of exposure, with 3 days of training in the Morris Water maze (4 trials per day spaced at 90 sec inter-trial intervals [ITI]). Rats were placed into the water maze at one of 4 positions along the perimeter, with a different release position to begin each trial. A probe trial assessed retention of platform location on the day after the final set of training trials. Four days after this probe trial, rats entered a working memory phase in which the platform was in a new location each day and a variable ITI of 1, 2, or 4 hr was inserted between Trials 1 and 2; Trials 3 and 4 followed at 90 sec intervals after Trial 2 on each day. The "savings" in latency to find the platform and distance traveled before finding it from Trial 1 to Trial 2 on each day served as an index of working memory. Ethanol-exposed rats showed similar acquisition of spatial navigation as control rats during training, as well as similar retention of platform location during the probe trial. However, rats exposed to average BAL >200 mg% showed accelerated forgetting, with decreased retention of platform location at the 2 hr ITI (p<.05), compared to control rats. Therefore, a 4-week history of intermittent ethanol exposure at BAL in excess of 200 mg% during periadolescence led to a working memory deficit in young adult rats, demonstrated by accelerated forgetting of novel information. These behavioral data are consistent with findings from adolescent human studies, indicating that binge-style alcohol exposure during the periadolescent stage of development is associated with deficits in retention of information.

Chronic periadolescent alcohol consumption produces persistent cognitive deficits in rhesus macaques

“…Thus, these data show that the effects were produced by chronic alcohol consumption itself and are not attributable to pre-existing factors such as those that complicate clear interpretation of human studies (Whipple et al, 1991, Polich et al, 1994, Tapert and Brown, 2000, Hill et al, 2001). The present conclusions are also consistent with other pre-clinical data from rodent models showing that repeated alcohol consumption during adolescence produces persistent cognitive deficits (Santin et al, 2000, Sircar and Sircar, 2005, Schulteis et al, 2008). …”

Attention, impulsivity, and cognitive flexibility in adult male rats exposed to ethanol binge during adolescence as measured in the five-choice serial reaction time task: the effects of task and ethanol challenges

“…Indeed, in the Slawecki (2006) study, when the task difficulty was increased by randomly alternating stimulus durations (0.5, 0.25, or 1 s) within the session, no differences in choice accuracy were found between ethanol-exposed and control rats (Slawecki 2006). Furthermore, adolescent rats exposed to different ethanol regimens showed similar acquisition of spatial navigation in the Morris water maze task (Obernier et al 2002; Schulteis et al 2008) and eight-arm radial maze (White et al 2000a) during adulthood compared with controls. However, young adult rats that had been exposed to ethanol during the periadolescent period exhibited working memory deficits in spatial navigation in the Morris water maze during a memory retention test, indicating accelerated forgetting of novel information compared with controls (Schulteis et al 2008).…”

Alcohol Consumption and Executive Functions in Adolescents: A Systematic Review

“…Considerando la inclusión de la memoria visoespacial, este componente fue el más estudiado por los artículos localizados en la presente revisión: de la totalidad de las publicaciones localizadas, nueve (69,23 %) evaluaron este componente, de las cuales cuatro estudiaron la memoria de trabajo (38,42,45,46) y cinco el desempeño y la memoria visoespacial (31,(41)(42)(43)47). Respecto a la memoria de trabajo, el 50 % encontró que el consumo de alcohol con patrón binge puede alterar el desempeño de este proceso (45,46).…”

“…Respecto a la memoria de trabajo, el 50 % encontró que el consumo de alcohol con patrón binge puede alterar el desempeño de este proceso (45,46). Cabe señalar que uno de estos estudios se realizó en ratas Wistar.…”