Sex Differences in Alcohol Preference and Drinking Patterns Emerge during the Early Postpubertal Period in Sprague‐Dawley Rats

Abstract

Young male and female Sprague-Dawley rats (30 days old) were assigned randomly to three treatment groups: (1) alcohol treatment--received beer with 5% ethanol added, food, and water ad libitum; (2) pair-fed treatment--received nonalcoholic beer plus sucrose and food to match intake by the alcohol-treated animals; and (3) control treatment--received food and water ad libitum. Animals were tested for alcohol preference for 24 hr and then received their assigned treatments for a period of 30 days, followed by a period of abstinence before alcohol preference testing again at 74 days of age. Males given free access to beer and water did not drink large quantities of beer. Females given free access to beer and water drank a lot of beer on the first day, but decreased intake until approximately 52 days of age. A developmental change in young female rats at approximately 52 days of age resulted in increased voluntary ethanol intake, possibly caused by hormonal changes associated with the establishment of estrous cycles. When the animals were tested for alcohol preference at 74 days of age after a period of abstinence, males and females in the pair-fed group had greater alcohol preference than animals in the other groups. Females in the pair-fed group had greater alcohol intake based on body weight than males in the pair-fed group and males and females in all other groups. These results provide insight into sex differences in the development of voluntary drinking behavior and responses of drinking behavior to the early stress of pair-feeding.

The adolescent brain and age-related behavioral manifestations

“…Preliminary evidence supports the suggestion that adolescent rats may display 2-3 times higher levels of ethanol intake relative to their body weights than do more mature animals ( [307]; Bannoura and colleagues, unpublished observations), reminiscent of findings that heavy alcohol use in humans is likewise often "adolescence-limited" (e.g. Ref.…”

Time Course of Elevated Ethanol Intake in Adolescent Relative to Adult Rats Under Continuous, Voluntary‐Access Conditions

“…Although few studies using animal models have compared voluntary ethanol intake in adolescents and adults, several of the available studies have reported that elevated ethanol consumption is not limited to human adolescents (Doremus et al, 2005;Lancaster et al, 1996). In other studies, however, relatively moderate levels of voluntary ethanol intake have been reported in adolescent Long-Evans rats (Honey and Galef, 2003;Siciliano and Smith, 2001), although these studies were not designed to directly compare adolescent ethanol consumption with that of adults.…”

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

“…The risk of extensive alcohol use is increased during adolescence, with 12% of 8 th graders, 22% of 10 th graders, and one fourth of 12 th graders (25%) reporting binge drinking (i.e., five or more drinks per occasion) during the past 2 weeks [17]. Elevated levels of ethanol intake are not restricted to human adolescents but can also be observed in adolescents of other species, with intake of ethanol being at least 2 times higher in adolescent rats than in their more mature counterparts under a number of test circumstances [3,7,20]. 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.…”