Evaluation and Characterization of Mouse Scratching Behavior by a New Apparatus, MicroAct

We evaluated and characterized the mouse scratching behavior using a new apparatus, MicroAct. Scratching behavior was evoked in ICR and BALB/c mice by compound 48/80, passive cutaneous anaphylaxis or repeated hapten application. Under the present experimental condition, MicroAct detected consecutive scratching behavior (events) consisting of 3 or more beats. Although the detecting standard of MicroAct was not identical to that of an observer, the number of events detected by MicroAct and by an observer were almost comparable with each other. Frequency of events, total scratching time and total number of beats detected by MicroAct increased depending on the intensity of the causing stimuli for scratching. In contrast, the duration of each event and the number of beats in each event increased only slightly, but the scratching speed was almost constant. The present results demonstrate that MicroAct is a useful tool for evaluating mouse scratching behavior. Mouse scratching behavior seems to have a relatively fixed pattern and the causing stimulus increases mainly in the frequency of event without affecting the scratching speed.