Gonadal hormones, but not sex, affect the acquisition and maintenance of a Go/No-Go odor discrimination task in mice

Abstract

In mice, olfaction is crucial for identifying social odors (pheromones) that signal the presence of suitable mates. We used a custom-built olfactometer and a thirst-motivated olfactory discrimination Go/No-Go (GNG) task to ask whether discrimination of volatile odors is sexually dimorphic and modulated in mice by adult sex hormones. Males and females gonadectomized prior to training failed to learn even the initial phase of the task, which involved nose poking at a port in one location obtaining water at an adjacent port. Gonadally intact males and females readily learned to seek water when male urine (S+) was present but not when female urine (S-) was present; they also learned the task when non-social odorants (amyl acetate, S+; peppermint, S-) were used. When mice were gonadectomized after training the ability of both sexes to discriminate urinary as well as non-social odors was reduced; however, after receiving testosterone propionate (castrated males) or estradiol benzoate (ovariectomized females), task performance was restored to pre-gonadectomy levels. There were no overall sex differences in performance across gonadal conditions in tests with either set of odors; however, ovariectomized females performed more poorly than castrated males in tests with non-social odors. Our results show that circulating sex hormones enable mice of both sexes to learn a GNG task and that gonadectomy reduces, while hormone replacement restores, their ability to discriminate between odors irrespective of the saliency of the odors used. Thus, gonadal hormones were essential for both learning and maintenance of task performance across sex and odor type.

The autism/neuroprotection-linked ADNP/NAP regulate the excitatory glutamatergic synapse

“…Interestingly, we have previously shown increased resilience in females vs. males in the hanging wire performance in an ALS mouse model 5 , which was further corroborated by a later comparative study 59 . Regarding sex differences in odor discrimination observed here, a very recent study suggests that this depends on gonadal steroids 60 , and here we add potential regulation by NAP, in a sex-dependent manner. Furthermore, our results (Fig.…”

Hormonal regulation of social ascent and temporal patterns of behavior in an African cichlid

“…Pre-pubertal rats perform more perseverative behavior compared to post-pubertal and adult rats during the water maze task (Juraska and Willing, 2017). Critically, gonadectomized male and female rats performed poorly at a go/no-go task measuring urinary odor sex discrimination, but after receiving testosterone implants, both sexes performed significantly better (Kunkhyen et al, 2018).…”

The association between olfactory dysfunction and cardiovascular disease and its risk factors in middle-aged and older adults

“…After adjusting for confounders, a strong association between CAD and olfactory dysfunction was observed among the males, whereas the association between abdominal obesity and olfactory dysfunction was significant in females. Changes in gonadal hormone levels with age may contribute to the observed differences in olfactory dysfunction and cardiovascular risk factors with gender, especially in women [43][44][45][46] . Estrogen change is known to be linked to fat distribution after menopause, as well as to the prevalence of abdominal obesity which increases with age 47 .…”