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. Author manuscript; available in PMC: 2011 Feb 1.
Published in final edited form as: Psychopharmacology (Berl). 2009 Dec 15;208(3):475–486. doi: 10.1007/s00213-009-1746-6

Figure 4. Training for co-administration of nicotine and alcohol.

Figure 4

A. Mean (± sem) reinforcements of nicotine and alcohol obtained prior to (Day −3 to 3) and after (Day 4 to 18) initiation of co-administration sessions. Days −3 to −1, show the numbers of alcohol reinforcements on the last three days of training with alcohol (0.19 ml, 12% w/v) alone at FR-3 are presented. On Days 1–3, the mean numbers of nicotine reinforcements (30 µg/kg/infusion) earned on the last three days of training for nicotine self-administration at FR-3 are shown. The break in the graph depicts the interval during which i.v. surgery, recovery and the initial training for nicotine self-administration occurred (30 days). B. Mean alcohol and nicotine reinforcements obtained by animals on Day −2 (alcohol) and 3 (nicotine), depicted in 5 min intervals. C. Mean reinforcements obtained by animals trained to co-administer alcohol and nicotine on Day 11 of co-administration, in 5 min intervals. For all graphs, N=34. * Significantly different from the average number of nicotine reinforcements on Days 1–3 (p<0.05). + Significantly different from preceding intervals for alcohol (p<0.05). # Significantly different from preceding intervals in nicotine alone group (p<0.05).