Adolescent ethanol sensitivity: hypothermia and acute tolerance.

A two-injection paradigm was used to assess acute (within-session) tolerance to ethanol in telemetry-implanted adolescent and adult rats. Male rats were intragastrically pretreated with either 1.0 g/kg of ethanol or water and then challenged with 2.0 g/kg of ethanol or water when blood alcohol levels (BALs) of ethanol-pretreated animals were anticipated to approach zero. Adults showed more rapid and sustained ethanol-induced hypothermia than adolescents. Acute tolerance to ethanol-induced hypothermia did not emerge clearly with the two-injection paradigm; ethanol-pretreated animals of both ages generally did not differ from those pretreated with water in their hypothermic response to ethanol despite higher BALs after the second intubation. Housing condition (paired or isolated) had little influence on ethanol-induced hypothermia. The adolescent attenuation of ethanol-induced hypothermia in this experiment was not associated with greater expression of within-session (acute) tolerance.