Fig. 3.
Mean (± S.E.M.) responses per session on the lever previously associated with the delivery of water in P rats given saline (n = 4–5/time point), or 0.1, 0.3, or 1.0 mg/kg nicotine (n = 6–10/dose/time point) subcutaneously immediately or 4-hr prior to the first PSR session. Upper Panel: asterisk (*) indicates that rats administered 0.3 mg/kg nicotine responded significantly (p < 0.05) less on the water lever during the first PSR session compared to extinction baseline levels. There were no significant water responding differences when animals were administered saline or 0.1 or 1.0 mg/kg of nicotine immediately prior to the first PSR session. Lower Panel: asterisk (*) indicates that rats administered saline or 0.1 mg/kg nicotine 4-hr prior to the first session responded significantly (p < 0.05) more on the water lever during the first PSR session compared to extinction baseline levels. There were no significant water responding differences when animals were administered 0.3 or 1.0 mg/kg nicotine 4-hr prior to the first PSR session.