Step Description Equipment Data collected 1 CC mice crossed to generate 73 RIX lines. - - 2 Baseline (pre-drug treatment) testing. At 8 weeks (-/+ 7 days) of age, body weight recorded. Additionally, extrapyramidal symptoms (EPS) assessed (-5 days) and mice subjected to open field test. Balance scale, inclined screen setup, open field arena Body weight, inclined screen test parameter (latency to move all four paws), open field test parameters (spontaneous locomotor activity, number of vertical beam breaks, time spent in center of arena, and number of beam breaks to determine stereotypic activity). 3 At 8 weeks of age (-/+ 7 days) or day 0, mice anesthetized and implanted with slow-release pellets containing either haloperidol or placebo. Two pellets implanted 2 days apart. Gas anesthetic delivery system, trocar - 4 24hr after the 2nd pellet implantation mice assessed for EPS (acute drug treatment) Inclined screen setup Latency to move all four paws. 5 At 28 days post-drug treatment mice weighed, and subjected to open field test in a similar manner as at baseline. Mice then immobilized and monitored to evaluate vacuous chewing movements (VCMs). Together these are considered chronic drug treatment assessment. Balance scale, open field arena, Observer XT video analysis system Body weight, open field test parameters (spontaneous locomotor activity, number of vertical beam breaks, time spent in center of arena, and number of beam breaks to determine stereotypic activity). Subtle and overt VCMs recorded as well as tongue protrusions and jaw tremors. 6 At +32 days post-treatment mice were sacrificed. Blood plasma collected from haloperidol treated mice. Mass spectrometer Plasma haloperidol concentration
General Information for All Procedures: CC RIX mice were aged for approximately 8 weeks before being assessed for various phenotypes. Phenotype assessment occurred pre-drug (7 days before pellet implantation), after acute drug treatment (on day 4; one day after split pellet implantation), and chronic treatment with haloperidol or placebo (chronic drug: 28-35 days after pellet implantation). The incline screen test which assess extrapyramidal symptoms (EPS) was carried out both pre-drug, and after acute drug treatment. Open field test was carried out both pre-drug and after chronic drug treatment. Vacuous chewing movements (VCMs) were assessed after chronic treatment, as were haloperidol levels in blood plasma. Six mice were removed from the study due to technical difficulties in phenotyping.
Giusti-Rodríguez P, Xenakis JG, Crowley JJ, Nonneman RJ, DeCristo DM, Ryan A, Quackenbush CR, Miller DR, Shaw GD, Zhabotynsky V, Sullivan PF, Manuel de Villena FP, Zou F. Antipsychotic Behavioral Phenotypes in the Mouse Collaborative Cross Recombinant Inbred Inter-Crosses (RIX). G3 (Bethesda). 2020 Sep 2;10(9):3165-3177. doi: 10.1534/g3.120.400975.