Hyposmia for butanol and vanillin in mutant staggerer male mice.

To address the hypothesis that reproductive deficits in male house mice expressing the staggerer mutation are due to chemosensory deficits, we examined behavioral responses to odorants. Two-choice tests (butanol or vanillin vs. amyl acetate odors) were used to determine behavioral thresholds for butanol, an aversive odor, and for vanillin, an attractive odor. Two groups of C57B1/6 male mice (one nonmutant group and one mutant group) were studied using an olfactometer. Different concentrations of butanol were used: from 5.5 x 10(-4) M to 5.5 x 10(-1) M. Vanillin at different concentrations, from 6.6 x 10(-5) M to 6.6 x 10(-2) M, was presented during the tests after a 1-month period of familiarization. Aversive and attractive behavioral thresholds of staggerer mice were higher than those of nonmutant mice. The staggerer mutation induces hyposmia in mice. This olfactory deficit could explain, at least partially, abnormalities in the social and sexual behaviors of staggerer mice.