Behavior Changes used to Test Olfactory Damage in Mice

Abstract

Degeneration of the olfactory mucosa of mice caused by certain drugs and irritant gas has been described. However, most histological reports contain no tests of behavior.This report describes the development of a simple behavioral procedure to investigate the effects of zinc sulphate and kanamycin on the olfactory sensitivity of mice.A paper towel marked with a center line was placed on the floor of a 30×25×18cm cage with transporent walls. Fifteen odors were placed in spots on one half of the field, and 15 odorless oil were distributed on the other side. The mouse was placed in the center of the field, and the time spent on each side was measured during a 300sec test period.1) In the control experiment, odorless oil was placed in spots on both sides. The average time spent on one side was 149sec (n=15). When isovaleric acid was used, the average time spent on that side was 56sec, a significant difference.2) Diminishing the concentration of the test odor, increased the average time spent on that side.3) Five days after nasal irrigation with a 1% aqueous solution of zinc sulphate, the average time spent on the odor side was 146sec. This clearly shows a severe olfactory disturbance. Subsequently, the time spent on the odor side decreased gradually. Eighty days after treatment, the time spent on odor side was approximately equal to before treatment, indicating recovery of olfactory sensitivity.4) Nasal irrigation with a 5% aqueous solution of kanamycin for 20 days, also significantly increased the time spent on the odor side.5) This method can be used to invetigsate the effect of various substances on the olfactory sensitivity of mice.