Procedure. PMA
(4 μg per ear) in 20 μL of acetone is applied to the both ear
of each mouse. The left ear (control) receives the vehicle.
Test drug is administered 1 h before PMA application. Two
control groups are used, a group with application of PMA
on the right ear and a positive control group that receive
standard drug. Six hours after PMA application, the mice
are killed by cervical dislocation and a 6 mm diameter disc
from each ear is removed with a metal punch and weigh. Ear
edema is calculated by subtracting the weight of the left ear
(vehicle) from the right ear (treatment) and is expressed as a
reduction in weight with respect to the control group.