Wesson Daniel W, Keller Matthieu, Douhard Quentin, Baum Michael J, Bakker Julie
Department of Biology, Boston University, Boston, MA 02215, USA.
Horm Behav. 2006 May;49(5):580-6. doi: 10.1016/j.yhbeh.2005.12.013. Epub 2006 Jan 30.
We asked whether odor discrimination abilities are sexually dimorphic in mice and, if so, whether the perinatal actions of estradiol contribute to these sex differences. The ability to discriminate different types of urinary odors was compared in male and female wild-type (WT) subjects and in mice with a homozygous-null mutation of the estrogen synthetic enzyme, aromatase (aromatase knockout; ArKO). Olfactory discrimination was assessed in WT and ArKO male and female mice after they were gonadectomized in adulthood and subsequently treated with estradiol benzoate. A liquid olfactometer was used to assess food-motivated olfactory discrimination capacity. All animals eventually learned to distinguish between urinary odors collected from gonadally intact males and estrous females; however, WT males as well as ArKO mice of both sexes learned this discrimination significantly more rapidly than WT females. Similar group differences were obtained when mice discriminated between urinary odors collected from gonadally intact vs. castrated males or between two non-social odorants, amyl and butyl acetate. When subjects had to discriminate volatile urinary odors from ovariectomized female mice treated with estradiol sequenced with progesterone versus estradiol alone, ArKO females quickly acquired the task whereas WT males and females as well as ArKO males failed to do so. These results demonstrated a strong sex dimorphism in olfactory discrimination ability, with WT males performing better than females. Furthermore, female ArKO mice showed an enhanced ability to discriminate very similar urinary odorants, perhaps due to an increased sensitivity of the main olfactory nervous system to adult estradiol treatment as a result of perinatal estrogen deprivation.
我们探究了小鼠的气味辨别能力是否存在性别差异，若存在，雌二醇在围产期的作用是否导致了这些性别差异。比较了雄性和雌性野生型（WT）小鼠以及雌激素合成酶芳香化酶纯合缺失突变小鼠（芳香化酶基因敲除；ArKO）辨别不同类型尿液气味的能力。在成年后对WT和ArKO雄性及雌性小鼠进行性腺切除，随后用苯甲酸雌二醇进行处理，之后评估它们的嗅觉辨别能力。使用液体嗅觉计评估以食物为动机的嗅觉辨别能力。所有动物最终都学会了区分从性腺完整的雄性和处于发情期的雌性收集的尿液气味；然而，WT雄性以及两性的ArKO小鼠比WT雌性更快地学会了这种辨别。当小鼠区分从性腺完整与阉割雄性收集的尿液气味或两种非社交性气味剂（戊酯和乙酸丁酯）时，也获得了类似的组间差异。当受试者必须区分经雌激素与孕酮序贯处理的去卵巢雌性小鼠与仅用雌激素处理的去卵巢雌性小鼠的挥发性尿液气味时，ArKO雌性小鼠很快学会了这项任务，而WT雄性和雌性以及ArKO雄性小鼠则未能做到。这些结果表明嗅觉辨别能力存在强烈的性别差异，WT雄性比雌性表现更好。此外，雌性ArKO小鼠表现出更强的辨别非常相似尿液气味剂的能力，这可能是由于围产期雌激素缺乏导致主要嗅觉神经系统对成年期雌二醇处理的敏感性增加。
