Journal: bioRxiv

Article Title: Morphine-context associative memory and locomotor sensitization in mice are modulated by sex and context in a dose-dependent manner

doi: 10.1101/2023.11.03.565492

Figure Lengend Snippet: A) Experimental timeline of the conditioned place preference (CPP) paradigm. B) Illustration of the CPP apparatus in the low and high context version of the apparatus. In the low context version, the walls were distinctly patterned with horizontal stripes in the “left” compartment and zig zag stripes in the “right” compartment, but the flooring was smooth in both compartments. In the high context version, the flooring was also distinct between compartments, with the “left” compartment altered to a textured rubber flooring to distinguish it tactilely from the “right” compartment smooth flooring. C-D) % Time spent in the left compartment of the apparatus in the low ( C ) and high ( D ) context versions of the apparatus on the pretest, when mice could freely explore both compartments of the apparatus for the first time. Individual data points are color coded to reflect categorization of compartment bias on the pretest (pink: > 55%; teal: < 45%; black: between 45% and 55% in left compartment). *p < 0.05 for unpaired t-tests between males and females; # p < 0.05, #### p < 0.0001 for one-sample t-tests within group compared to the null hypothesis mean of 50%. E-F) Pretest locomotion in females and males, subcategorized by compartment bias of 55% as defined in C and D . Females had greater pretest locomotion than males in both the low ( E ) and high ( F ) context versions of the assay, but locomotion was unaffected by compartment bias. *p < 0.05, ****p < 0.0001 for main effects of sex in 2×2 ANOVAs.

Article Snippet: The CPP apparatus consisted of a standard mouse arena (27.3×27.3×20.3 cm) separated into two compartments by a two chamber place preference insert with removable guillotine door (Med Associates Inc., Fairfax, VT, USA).

Techniques: Conditioned Place Preference

Journal: bioRxiv

Article Title: Morphine-context associative memory and locomotor sensitization in mice are modulated by sex and context in a dose-dependent manner

doi: 10.1101/2023.11.03.565492

Figure Lengend Snippet: A-B) On the first day of conditioning (C1) in the low context ( A ) and high context ( B ) versions of the CPP assay, females displayed acute hyperlocomotion following the morphine injection on the afternoon conditioning session, regardless of whether the morphine was paired with the left or right compartment; this locomotor sensitivity was dose-dependent, as cohorts receiving higher doses of morphine displayed greater morphine-induced hyperlocomotion. Locomotion following saline injection on the morning session (6 hr earlier) was similar across morphine dose groups and paired compartment. C-D) Males displayed a similar dose-dependent hyperlocomotor response to morphine that was similar in both compartments of the apparatus in the low ( C ) and high ( D ) context assays, with no differences in saline locomotion. **p < 0.01, ****p < 0.0001 indicate main effect of morphine dose in 2×2 RM-ANOVAs; $$$ p ≤ 0.001, $$$$ p < 0.0001 indicate difference from 5 mg/kg morphine dose, ## p ≤ 0.01, ### p ≤ 0.001 indicates difference from 10 mg/kg morphine dose in post hoc t-tests between doses.

Article Snippet: The CPP apparatus consisted of a standard mouse arena (27.3×27.3×20.3 cm) separated into two compartments by a two chamber place preference insert with removable guillotine door (Med Associates Inc., Fairfax, VT, USA).

Techniques: Injection, Saline