According to the protocol of Vengeliene et al.,45,46 8 P rats, 7 HAD rats, and 7 AA rats were given ad libitum access to tap water and to 5%, and 20% ethanol solution (v/v). All rats underwent a two-week deprivation cycle after 8 weeks of continuous alcohol availability. After the deprivation period, rats were given access to alcohol again and 3 more two-week deprivation periods were introduced in a random manner (the duration between deprivation periods varied between 4 and 16 weeks). The long-term voluntary alcohol drinking procedure, including all deprivation phases, lasted a total of 52 weeks. Total ethanol intake (g/kg of body weight/day) was calculated as the daily average across 7 measuring days. For comparison, 3 age- and weight-matched control groups, consisting of 7 P rats, 6 HAD rats, and 7 AA rats, experienced identical handling procedures for the entire duration of the experiment, but did not receive alcohol.
