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. Author manuscript; available in PMC: 2010 Apr 1.
Published in final edited form as: Psychopharmacology (Berl). 2008 Aug 8;203(2):355–367. doi: 10.1007/s00213-008-1270-0

Figure 4.

Figure 4

Average percentage of responding on the nicotine-appropriate lever (top panels) and response rates (bottom panels) from generalization and combination tests with adenosine antagonists in nicotine-trained rats chronically exposed to caffeine in their drinking water. A) Effects of pretreatment with nicotine (n = 12), caffeine (n = 11), CPT (n = 8–10), or MSX-3 (n = 8–10) in nicotine-trained rats. B) Nicotine dose-response curves after pretreatment with vehicle, CPT, MSX-3, or caffeine (n = 11–12). Data are means ± S.E.M. *p < 0.05, **p < 0.01, post hoc comparison with the vehicle pretreatment after significant ANOVA for repeated measures main effect, Dunnett’s test. Numbers with asterisks at higher doses indicate the number of rats that completed at least one fixed ratio (trial) during the session over the total number of rats in which the dose was tested.