Fig. 11.

Effects of coadministration of a subthreshold dose of donepezil (0.5 mg/kg), an active dose of S-(−)-cotinine (10 mg/kg), and the nicotinic antagonists methyllycaconitine (A) and dihydro-β-erythroidine (B) on performance of a spontaneous novel object recognition task. In these experiments, the antagonist was administered first (60 minutes before the NOR training trial) followed 30 minutes later (i.e., 30 minutes before the NOR training trial) with the combination of donepezil and cotinine. All compounds were administered by intraperitoneal injection. Mean (± S.E.M.) exploration times of the familiar and novel objects after 48-hour delays (A/B retention sessions) are illustrated in the main figures. Insets illustrate the mean (± S.E.M) discrimination (d2) ratios. d2 ratio = (novel × familiar)/(novel + familiar). ⁺⁺⁺P < 0.001, novel versus familiar object; ***P < 0.001, significantly different from vehicle response. COT, cotinine; DON, donepezil. N = 8 for each group.