Effects of cannabinoid receptor ligands (CB ligands) on the working memory-related behavioral alterations (SAP rate (%)) caused by repeated nicotine (NC) and/or immobilization stress (IM) in the Y-maze test. Data of SAP rate are presented for groups of mice co-treated with AM (a), CP (b) and VD (c). The values at the 2 h time point after the last NC (0.8 mg/kg, s.c.) or IM treatment are shown as means ± S.D. (n=10 for each group). The abbreviations of the co-administered CB ligands with each i.p. dose (mg/kg) are noted in the text. The data for the control, NC, IM, and NC plus IM (NC-IM) groups without any CB ligand co-treatments, as well as the CB ligand-only groups, are also shown. * (p<0.05), ** (p<0.01): significant attenuation as compared to the control group; + (p<0.05), ++ (p<0.01): significant increase as compared to the NC, IM, or NC plus IM (NC-IM) group without any CB ligand co-treatments.