Voluntary Binge Consumption of Ethanol in a Sweetened, Chocolate-Flavored Solution by Male and Female Adolescent Sprague Dawley Rats

Abstract

The still maturing adolescent brain may be particularly vulnerable to lasting consequences of ethanol (EtOH) exposure. Yet, human adolescents are the age group most likely to engage in binge drinking (a pattern of drinking leading to blood EtOH concentrations (BECs) of 80mg/dl or greater). Most studies to date assessing the long-term effects of adolescent EtOH exposure in outbred rodent populations have either used experimenter-administered EtOH to produce BECs in the binge range or assessed voluntary intake of EtOH at well below binge levels. Beginning with a modified schedule-induced polydipsia (SIP) procedure, this study examined the suitability of several approaches to induce voluntary binge-like consumption during adolescence in an outbred rat strain. Adolescent male and female Sprague Dawley rats were food deprived to 85% projected free-feeding weights beginning on postnatal day (P) 24 and were given 30minutes of access to 10% EtOH in chocolate Boost® or Boost® alone daily from P28 to P41 (followed later by their daily allocation of food). Animals were tested within operant chambers (Exp. 1a, 1b and Exp. 2) or home and novel cages (Exp. 3). Animals received either scheduled delivery of banana pellets to examine SIP (Exp. 1a,b) or massed pellet presentation (Exp. 2 and Exp. 3). Blood samples were collected via the lateral tail vein on P33 and P41. Intakes produced BECs frequently in the binge range (>80mg/dl) and modeled binge-like consumption patterns, with high consumption days typically followed by 1 to 2days of lower consumption; this variability was less evident with Boost® alone. Consumption was not schedule induced and was generally high across all studies, although consumption in males appeared to be particularly pronounced when animals were tested in the presence of their cage mate. Binge-like patterns of EtOH consumption were produced using these procedures in adolescent Sprague Dawley rats of both sexes and may prove to be a useful model for work examining the short- and long-term consequences of high levels of voluntary EtOH intake in adolescence.