Project protocol — Contents
Workflow and sampling
Equipment
Reagents, supplies, and solutions
Procedure for testing open field activity
Data
Definitions and formulas
References
Workflow
Mice are brought from the vivarium to the test room and acclimated before testing begins After acclimation to testing environment, mice are given treatment vehicle (saline) and placed in an open field test (OFT) apparatus to measure baseline activity Mice are brought from the vivarium to the test room and acclimated before testing begins After acclimation to testing environment, mice are given treatment vehicle (saline) and placed in an OFT apparatus to measure level of habituation Mice are brought from the vivarium to the test room and acclimated before testing begins After acclimation to testing environment, mice are given stimulant methamphetamine and placed in an OFT apparatus to measure increase level of locomotor activity Open field chambers:
- Total distance traveled is measured using automated Versamax Animal Activity Monitoring System (AccuScan, Columbus, OH).
- Each chamber is made of a clear acrylic arena (40 X 40 X 30 cm) placed inside a frame containing evenly spaced photocells and receptors making a grid of infrared photobeams from the front to the back and from the left to the right of the arena.
- Each activity chamber is surrounded by a sound attenuating PVC / lexan environmental chamber (Med Associates, Inc.).
- In each chamber overhead lighting provides dim illumination (~80 lux) and a fan provides ventilation and masking of background noise.
- Vehicle: Saline (0.9% NaCl)
- Drug: Methamphetamine (2 mg/kg, i.p.)
- Disinfectant: 10% isopropanol was used to clean the open field chambers between sessions
Acclimation to test conditions
Testing is conducted during the light phase between 08:00 and 16:00 h. Mice are transported from the vivarium into the test room and are allowed to habituate for at least 30 min before testing.
Procedure for testing open field activity
Mice of both sexes are tested for all 20 CSS strains and B6 and A/J. Mice ranged from 7-16 weeks old at the first day of testing. An N of at least 6 mice per sex per strain are used for each strain with the exception of CSS-13 (N=3 males, N=9 females).
Day 1: Mice are placed in individual holding cages for approximately 5 min and then receive an intraperitoneal (i.p.) injection of saline vehicle. Mice are immediately placed in the center of the open field and their activity recorded for total distance traveled over 30 min. Mice are then returned to their home cage.
Day 2: Mice are placed in individual holding cages for approximately 5 min and then receive an intraperitoneal injection of saline vehicle. Mice are immediately placed in the center of the open field and their activity recorded for total distance traveled over 30 min. Mice are then returned to their home cage.
Day 3: Mice are placed in individual holding cages for approximately 5 min and then receive an intraperitoneal injection of methamphetamine. Mice are immediately placed in the center of the open field and their activity recorded for total distance traveled over 30 min. Mice are then returned to their home cage.
• In between sessions, the open field chamber is cleaned with 10% alcohol.
Data collected by investigator
30 min activity in the open field following saline injection on Day1, 30 min activity in the open field following saline injection on Day2, and 30 min activity in the open field following methamphetamine treatment on Day3 .
Habituation: Day 1 activity – Day 2 activity
Normalization of methamphetamine activity: Day 3 activity – Day 1 activity
Normalization of methamphetamine activity: Day 3 activity – Day 2 activity
References
Bryant CD, Chang HP, Zhang J, Wiltshire T, Tarantino LM, Palmer AA. A major QTL on chromosome 11 influences psychostimulant and opioid sensitivity in mice. Genes Brain Behav. 2009 Nov;8(8):795-805. Epub 2009 Jul 21.
PubMed 19694818 Bryant CD, Graham ME, Distler MG, Munoz MB, Li D, Vezina P, Sokoloff G, Palmer AA. A role for casein kinase 1 epsilon in the locomotor stimulant response to methamphetamine. Psychopharmacology (Berl). 2009 May;203(4):703-1Epub 2008 Dec 3.
PubMed 19050854 FullTextGrisel JE, Belknap JK, O'Toole LA, Helms ML, Wenger CD, Crabbe JC. Quantitative trait loci affecting methamphetamine responses in BXD recombinant inbred mouse strains. J Neurosci. 1997 Jan 15;17(2):745-54.
PubMed 8987796 Hamidovic A, Dlugos A, Palmer AA, de Wit H. Polymorphisms in dopamine transporter (SLC6A3) are associated with stimulant effects of D-amphetamine: an exploratory pharmacogenetic study using healthy volunteers. Behav Genet. 2010 Mar;40(2):255-6Epub 2010 Jan 21.
PubMed 20091113