Strains were serially tested on four floor types (see details below). Animals were randomized into two groups per strain.
Group 1 floor order: E, A, D, B
Group 2 floor order: A, E, D, B
Each mouse was tested before (saline control) and after EtOH treatment.
Each mouse was tested on four platforms of the parallel rod floor apparatus (see Equipment below) on a rotating 3-day injection schedule. Mice were undisturbed for six days between platforms.
* Recovery period before next platform
Day Injection Tested Data collected 1 Saline Yes Yes 2 Saline Yes Yes 3 EtOH Yes Yes 4-9 None * No No
Dose 2g EtOH per kg body weight [g/kg] Delivery intraperitoneal injection (i.p.)
Briefly, a clear acrylic box sits is placed on top of a parallel rod floor which is 1 cm above a base plate. The apparatus is set inside an activity monitor. The activity monitor is housed in a sound-insulated black acrylic chamber equipped with fluorescent lighting and a ventilating fan. Errors are recorded by an Apple IIE computer when a paw slips through the rods and completes an electrical circuit with the base plate. The activity monitor records horizontal distance traveled (detected by photocell beam breaks).
Parallel rod floor configurations
* A, B, D, E are described in Kamens et al., 2005.
Floor * (apparatus) Rod diameter (mm) Inter-rod distance (mm) A 1.6 4 B 1.6 6 D 3.2 6 E 4.8 6
Configuration C was not used for testing.
- Test agent: ethanol (EtOH), Pharmoco Inc, Brookfield CT, USA;
- EtOH solution prepared at 20% v/v in saline
- Saline (physiological saline): 0.9%, Baxter Healthcare Corp, Deerfield IL, USA
- Isopropyl alcohol: 10% for wipe downs between testsAcclimation to test conditions
Mice are acclimated to room environment 45-60 min before testing.
Procedure: Parallel rod floor test for motor incoordination
a. Randomly selected mice are i.p. injected with saline or EtOH.
b. Each mouse is immediately positioned in the center of the parallel rod floor apparatus (see Equipment above for details), and testing begins.
c. Mice are monitored and data collected over 15 min of testing.
d. The apparatus is cleared and wiped with 10% isopropyl alcohol after each test.
Distance traveled and number of paw slips (errors)
Definitions & formulas
Motor incoordination (err) = (#errors / distance traveled) x 100