Skip to main content
. 2020 May 21;14:75. doi: 10.3389/fnbeh.2020.00075

Figure 4.

Figure 4

Ketamine administration attenuates sucrose-induced conditioned place preference. (A) Timeline and sucrose regimen of the behavioral procedure. Following sucrose oral self-administration in the three-compartment apparatus, mice underwent EPM testing on post-conditioning day 1 (PC1). Twenty-four hours later, mice received no injection or (R,S)-ketamine (10 mg/kg, i.p.) 30 min before the conditioned place preference (CPP) test on post-conditioning day 2 (PC2). (B) A summary showing the milliliters of water or sucrose consumed for each training session in the least preferred chamber. Groups conditioned with sucrose (i.e., sucrose (sucr.) and sucrose + ketamine (sucr. + ket.) groups) drank significantly more than groups conditioned with water (i.e., water (Wat.) and water+ketamine (Wat. + Ket.) groups; F(15,175) = 462.1, p < 0.0001, two-way repeated-measures ANOVA, Bonferroni post hoc test). (C) A summary showing that conditioning with sucrose had no effect on anxiety-like behaviors as both water- and sucrose-conditioned mice displayed similar % time in the open arm of the EPM (t(17) = 0.184, p = 0.856, student’s t-test). (D) A summary showing that oral self-administration of sucrose produced CPP at PC2, which was blocked by (R,S)-ketamine treatment (F(3,35) = 6.31, p = 0.0015, one-way ANOVA, Bonferroni post hoc test). (E) A summary showing that ketamine injections 30 min before the CPP test did not impact entrance counts in the CPP apparatus (Sal. + Sal. vs. Sal. + Ket.: t(31) = 0.295, p = 0.770; Mor. + Sal. vs. Mor. + Ket.: t(21) = 1.13, p = 0.272; Wat. + Sal. vs. Wat. + Ket.: t(16) = 0.874, p = 0.395; Sucr. + Sal. vs. Sucr. + Ket.: t(19) = 1.43, p = 0.168, student’s t-test). (F) A summary showing that ketamine injections 30 min before the CPP test did not impact exploratory counts in the CPP apparatus (Sal. + Sal. vs. Sal. + Ket.: t(31) = 1.42, p = 0.166; Mor. + Sal. vs. Mor. + Ket.: t(21) = 0.045, p = 0.964; Wat. + Sal. vs. Wat. + Ket.: t(16) = 1.26, p = 0.226; Sucr. + Sal. vs. Sucr. + Ket.: t(19) = 1.80, p = 0.088, student’s t-test). *p < 0.05, **p < 0.01.