Response of male mice to odours of female mice in different stages of oestrous cycle: self-grooming behaviour and the effect of castration (original) (raw)
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Hormones and Behavior, 2006
We previously found that both male and female aromatase knockout (ArKO) mice, which cannot synthesize estrogens due to a targeted mutation of the aromatase gene, showed less investigation of volatile body odors from anesthetized conspecifics of both sexes in Y-maze tests. We now ask whether ArKO mice are in fact capable of discriminating between and/or responding to volatile odors. Using habituation/ dishabituation tests, we found that gonadectomized ArKO and wild-type (WT) mice of both sexes, which were tested without any sex hormone replacement, reliably distinguished between undiluted volatile urinary odors of either adult males or estrous females versus deionized water as well as between these two urinary odors themselves. However, ArKO mice of both sexes were less motivated than WT controls to investigate same-sex odors when they were presented last in the sequence of stimuli. In a second experiment, we compared the ability of ArKO and WT mice to respond to decreasing concentrations of either male or female urinary odors. We found a clear-cut sex difference in urinary odor attraction thresholds among WT mice: WT males failed to respond to urine dilutions higher than 1:20 by volume, whereas WT females continued to respond to urine dilutions up to 1:80. Male ArKO mice resembled WT females in their ability to respond to lower concentrations of urinary odors, raising the possibility that the observed sex difference among WT mice in urine attraction thresholds results from the perinatal actions of estrogen in the male nervous system. Female ArKO mice failed to show significant dishabituation responses to two (1:20 and 1:80) dilutions of female urine, perhaps, again, because of a reduced motivation to investigate less salient, samesex urinary odors. Previously observed deficits in the preference of ArKO male and female mice to approach volatile body odors from conspecifics of either sex cannot be attributed to an inability of ArKO subjects to discriminate these odors according to sex but instead may reflect a deficient motivation to approach same-sex odors, especially when their concentration is low. D
Effects of novel odours on the mating behaviour in mice
The aim of this study was to examine whether and how different odorants placed on the bodies of female mice, but having no reward value for the males, affect courtship and mating behaviour of male mice towards females in oestrus and thus emitting female pheromones. In this manner, certain consequences of concurrent activation of the main olfactory system and the vomeronasal system were investigated. Four different odorants (white musk, lavender, peppermint and valerian) were used for swabbing female mice in oestrus. Using a total of 160 sexually naive outbred mice of both sexes, divided for each of 4 odorants into controls (not swabbed with odorant) and two experimental groups, in the experimental group I the females observed previously as controls were swabbed with one of the 4 odorants, while in the experimental group II, new naive females were swabbed with one of the 4 odorants. The females were observed in individual cages for 30 min. each, together with a respective sexually naive male. The latency between introduction of a male into a cage with a previously swabbed female and initiation of courtship and mating behaviours by males (sniffing, circling, misdirected mounting, copulation failures, successful copulation) was recorded. Latency to the occurrence of all sexual behaviours was significantly longer in experimental groups compared to controls. Latency to initiation of courtship behaviour, especially sniffing and circling, was shorter towards females swabbed with peppermint odour than for other odorants, indicating no aversion to this odour. However, the peppermint odour completely inhibited copulation. It is concluded that alien volatile odours with no reward value nevertheless exert differentiated suppressing effects on female mice pheromones inducing courtship and mating behaviour. Thus, it is hypothesized that the activation of the main olfactory system suppresses the accessory vomeronasal system.
Animal Behaviour, 1985
The urine of intact, adult male mice elicits more investigatory sniffing from female mice than does the urine of castrated males. When either of two androgen-dependent urinary compounds, 2-sec-butyl dihydrothiazole or dehydro-exo-brevicomin are added to castrate urine, its relative attractiveness remains the same. When both compounds are added to castrate urine, however, its activity is enhanced and the castrate urine becomes as attractive to females as whole, intact male urine. Females exposed to the reconstituted 'normal' urine for 3 rain per day, displayed more frequent oestrus cycles. The two synthetic compounds are synergistic in the context of castrate urine, producing an olfactory message that behaviourally and physiologically mimics the activity of the normal biological signal.
Quantitative chromatographic profiling of odours associated with dominance in male laboratory mice
Aggressive Behavior, 1988
Triads of male NMRI mice were housed together and dominance hierarchies allowed to form. At age 19 weeks the mice were ranked on the basis of wins in spontaneous aggressive encounters, and whole-body volatiles were sampled by the dynamic solvent effect and quantitatively analysed by capillary gas chromatography. At age 26 weeks the mice were again ranked on the basis of wins in aggressive encounters, number of aggressive encounters initiated, and scent marking patterns, and whole-body volatiles were sampled and analysed. Chromatographic odour profde ranks agreed perfectly with aggressive initiator ranks and poorly with encounter winner ranks. Eight components of the whole-body odour were identified by gas chromatography-mass spectrometry; two of these are known semiochemicals. The results demonstrate that murine semiochemicals are accessible to quantitative analysis at the level of the individual.
Modulation of Exploratory Behavior in Female Mice by Protein-Borne Male Urinary Molecules
2002
Male pheromones are believed to attract females and repel male mice in open field tests but, when tested in more complex environments, they can attract male mice in usually avoided areas. Females were tested in an apparatus with one dark and one light side, in the absence or presence of male urine or the major urinary proteins (MUPs) bearing the natural ligands. Diestrous females were slower in leaving from the dark area when male urine or MUPs were present in it. Estrogen-primed females showed the opposite behavior, with an increase in the same latency. The light-avoidance behavior of prepubertal females, or females reared without males was not influenced by the presence of male chemosignals. The results show that adult female mice can react to MUPborne volatiles as to adult male urine and use them as cues of male mice, if they were previously exposed to male cues during infancy. MUP-borne molecules are, thus, the olfactory trace of males in the environment and modulate mice exploratory behavior.
Male chemosignals inhibit the neural responses of male mice to female chemosignals
Brain Research Bulletin, 2004
Reproductive function in mice is regulated by reproductively-stimulating and reproductively-inhibiting primer pheromones released by conspecifics. When experienced simultaneously, their responses to reproductively-inhibiting chemosignals take precedence over their responses to reproductively-stimulating chemosignals. For example, while female urine induces luteinizing hormone (LH) release in males, this response is blocked when male urine is presented in conjunction with female urine. In the present study, we examined the neural correlates of these responses to male and female urine. Sexually experienced, male CF1 mice were exposed to water, female urine, or a mixture of male and female urine. The resulting patterns of Fos-immunoreactivity (Fos-ir) were then compared between groups. Female urine induced significantly more Fos-ir within the main and accessory olfactory systems (MOS and AOS, respectively) than did water, male urine or mixed urine. Notably, within the main and accessory olfactory bulbs, male urine attenuated the responses of mitral cells, but not granule cells, to female urine. Overall, the results indicate that exposure to male urine inhibited the responses of cells within the MOS and AOS to female urine. The specific pattern of Fos-ir in the olfactory bulbs suggests that this may be due to an inhibition in the responses of mitral cells to female urine.
Behavioral selection of odor cues by young female mice affects age of puberty
Developmental Psychobiology, 1992
Female house mice were reared from weaning at 21 days of age until first vaginal estrus in 40 1 aquaria in which they were given a choice of exposing themselves to bedding placed on opposite halves of the aquarium floor and sprayed with water or urine containing puberty-influencing chemosignals. In Experimental I , mice housed with only male urine cues sprayed on the bedding matured significantly earlier and mice housed with only grouped female urine sprayed on the bedding matured significantly later than control mice where water was sprayed on the bedding for both halves of the aquarium. In Experiment 2, there were no significant differences in mean ages at vaginal introitus or first estrus for females reared with choices between (a) bedding sprayed with male urine versus bedding sprayed with water, (b) bedding sprayed with urine from grouped females versus bedding sprayed with water, (c) bedding sprayed with male urine versus bedding sprayed with urine from grouped females, or (d) the Reprint requests should be sent to Dr.
Hormones and Behavior, 2004
Half a century has passed since the first report of the influence of odors on mice. Odors are known to influence behavior (signaling effect) and affect the physiology (primer effect) of mice. This review focuses on summarizing the primer effects found so far in female and male mice. Odors from conspecifics of the opposite sex had the tendency to enhance reproductive activities, whereas odors from conspecifics of the same sex diminish them. Only 2,5-dimethylpyrazine, one of the odor components identified in group-housed females, has been reported to have a suppressive influence on both males and females by lowering reproductive activities. Studies showed progress from the discovery of phenomena to the identification of odor components that cause such changes in reproductive organs and related neuroendocrinological changes. Compared to studies on the mechanisms of primer effects in females, the mechanisms in males are not yet clarified, and detailed studies on effects on the reproductive organs are still in primitive stages especially for males. Hypotheses on the influence of changes in the concentration of testosterone, estrogen, and prolactin on spermatogenesis and sperm maturation after exposure to odors are discussed.
Chronic exposure of cat odor enhances aggression, urinary attractiveness and sex pheromones of mice
Journal of Ethology, 2008
To test whether predator odor exposure negatively affects the behavior of prey, we exposed three groups of male house mice (Mus musculus) to the odors of cat (Felis catus) urine, rabbit (Oryctolagus cuniculus) urine and water (control), respectively, for consecutive 58 days and investigated how the treatments affected the response, aggressiveness, dominance, urinary attractiveness to females and pheromone composition of male mice. Compared to mice exposed to rabbit urine or water, those exposed to cat odor did not show any response habituation to the cat odor and became more aggressive, increased mark urine production and were more attractive to females when the latter were tested with their urine. Furthermore, gas chromatography coupled with mass spectrometry analysis revealed coincident elevations of the well-known male pheromones, E,E-a-farnesene, E-b-farnesene, R,R-dehydroexo-brevicomin or S-2-sec-butyl-dihydrothiazole. In addition, rabbit urine exposure increased urinary attractiveness to females and pheromonal levels of the males in comparison with the mice exposed to water. This could be related to olfactory enrichment of heterospecific chemosignals, suggesting that predator odors were more beneficial. In light of these anti-intuitional findings in the chemical interaction between cats and mice, we conclude that predator odor affects prey more profoundly than previously believed and that its impact may not always be negative.