Skip to main content
. Author manuscript; available in PMC: 2014 Jan 1.
Published in final edited form as: Psychopharmacology (Berl). 2012 Aug 4;225(1):187–199. doi: 10.1007/s00213-012-2807-9

Figure 8.

Figure 8

Effects of combined treatment with 10 mg/kg of morphine (10 MS) and a NMDAR antagonist on development and expression of tolerance to discriminative stimulus effects of MS. Rats were trained to discriminate 3.2 mg/kg MS and saline and then received chronic treatment, shown in column titles, b.i.d. for 7 or 14 days. Tests of cumulative doses of MS were conducted before treatment and 12 h after the last injections on Day 7 or 14 of treatment; i.e., on Day 8 (D8) and Day 15 (D15). On test days, rats received SAL or an appropriate dose of NMDAR antagonist (in milligrams per kilogram) 30 min before tests. Other details as in Fig. 5. Text in italics identifies the −30-min pretreatment: SAL saline, 0.032 or 0.1 DZ 0.032 or 0.1 mg/kg dizocilpine