Table 1. Behavioral sensitization to nicotine procedure.

Phenotype pre-screened LRHR rats received saline (1 ml/kg; s.c.) or nicotine (0.35 mg/kg; s.c.) injections four times at 3-day intervals (PN 28–37). Following the last saline or nicotine injection, all animals underwent 1 wk of abstinence during which they received daily, systemic Y2R antagonist (20 mg/kg; i.p) or vehicle (1 ml/kg; i.p) injections. At the end of the abstinence period (PN 45), all animals were challenged with a low dose of nicotine (0.1 mg/kg; s.c.).