Bromodeoxyuridine (BrdU) was administered to a subset of rats to quantify survival of proliferating cells in nondependent and alcohol dependent self-administering rats. After 6 weeks of exposure to alcohol vapors (dependent) or control air (nondependent), 4 dependent and 6 nondependent rats were selected randomly and administered one injection of 150 mg/kg BrdU, i.p. (Boehringer Mannheim; dissolved in 0.9% saline and 0.007N NaOH at 20 mg/ml), at the same time into acute withdrawal (2-4 h) at which time they were normally tested for operant responding. Four alcohol-naive rats received BrdU injections also at this time. “Prolonged nondependent” (n = 6) and “prolonged dependent” (n = 4) rats were not tested for post-air/vapor alcohol self-administration after the BrdU injection, but both groups were returned to their chronic treatment environment (i.e., intermittent alcohol vapor exposure for dependent animals or air control for nondependent animals) for 28 days until perfusion.
