1
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Troconis EL, Seo C, Guru A, Warden MR. Serotonin neurons in mating female mice are activated by male ejaculation. Curr Biol 2023; 33:4926-4936.e4. [PMID: 37865094 PMCID: PMC10901455 DOI: 10.1016/j.cub.2023.09.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/31/2023] [Accepted: 09/28/2023] [Indexed: 10/23/2023]
Abstract
Sexual stimulation triggers changes in female physiology and behavior, including sexual satiety and preparing the uterus for pregnancy. Serotonin (5-HT) is an important regulator of reproductive physiology and sexual receptivity, but the relationship between sexual stimulation and 5-HT neural activity in females is poorly understood. Here, we investigated dorsal raphe 5-HT neural activity in female mice during sexual behavior. We found that 5-HT neural activity in mating females peaked specifically upon male ejaculation and remained elevated above baseline until disengagement. Artificial intravaginal mechanical stimulation was sufficient to elicit increased 5-HT neural activity but the delivery of ejaculatory fluids was not. Distal penis expansion ("penile cupping") at ejaculation and forceful expulsion of ejaculatory fluid each provided sufficient mechanical stimulation to elicit 5-HT neuron activation. Our study identifies a female ejaculation-specific signal in a major neuromodulatory system and shows that intravaginal mechanosensory stimulation is necessary and sufficient to drive this signal.
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Affiliation(s)
- Eileen L Troconis
- Biological and Biomedical Sciences Program, Cornell University, Ithaca, NY 14853, USA
| | - Changwoo Seo
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA; Cornell Neurotech, Cornell University, Ithaca, NY 14853, USA
| | - Akash Guru
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA; Cornell Neurotech, Cornell University, Ithaca, NY 14853, USA
| | - Melissa R Warden
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA; Cornell Neurotech, Cornell University, Ithaca, NY 14853, USA.
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2
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Troconis EL, Seo C, Guru A, Warden MR. Serotonin neurons in mating female mice are activated by male ejaculation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.14.540716. [PMID: 37645786 PMCID: PMC10461921 DOI: 10.1101/2023.05.14.540716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Sexual stimulation triggers changes in female physiology and behavior, including sexual satiety and preparing the uterus for pregnancy. Serotonin is an important regulator of reproductive physiology and sexual receptivity, but the relationship between sexual stimulation and serotonin neural activity in females is poorly understood. Here, we investigated dorsal raphe serotonin neural activity in females during sexual behavior. We found that serotonin neural activity in mating females peaked specifically upon male ejaculation, and remained elevated above baseline until disengagement. Artificial intravaginal mechanical stimulation was sufficient to elicit increased 5-HT neural activity but the delivery of ejaculatory fluids was not. Distal penis erectile enlargement ("penile cupping") at ejaculation and forceful expulsion of ejaculatory fluid each provided sufficient mechanical stimulation to elicit serotonin neuron activation. Our study identifies a female ejaculation-specific signal in a major neuromodulatory system and shows that intravaginal mechanosensory stimulation is necessary and sufficient to drive this signal.
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Affiliation(s)
- Eileen L. Troconis
- Department of Biological and Biomedical Sciences, Cornell University, Ithaca, NY 14853 USA
| | - Changwoo Seo
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853 USA
- Cornell Neurotech, Cornell University, Ithaca, NY 14853 USA
| | - Akash Guru
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853 USA
- Cornell Neurotech, Cornell University, Ithaca, NY 14853 USA
| | - Melissa R. Warden
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853 USA
- Cornell Neurotech, Cornell University, Ithaca, NY 14853 USA
- Lead Contact
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3
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Yin L, Lin D. Neural control of female sexual behaviors. Horm Behav 2023; 151:105339. [PMID: 36878049 PMCID: PMC10133197 DOI: 10.1016/j.yhbeh.2023.105339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/07/2023]
Abstract
Reproduction is the biological process by which new individuals are produced by their parents. It is the fundamental feature of all known life and is required for the existence of all species. All mammals reproduce sexually, a process that involves the union of two reproductive cells, one from a male and one from a female. Sexual behaviors are a series of actions leading to reproduction. They are composed of appetitive, action, and refractory phases, each supported by dedicated developmentally-wired neural circuits to ensure high reproduction success. In rodents, successful reproduction can only occur during female ovulation. Thus, female sexual behavior is tightly coupled with ovarian activity, namely the estrous cycle. This is achieved through the close interaction between the female sexual behavior circuit and the hypothalamic-pituitary-gonadal (HPG) axis. In this review, we will summarize our current understanding, learned mainly in rodents, regarding the neural circuits underlying each phase of the female sexual behaviors and their interaction with the HPG axis, highlighting the gaps in our knowledge that require future investigation.
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Affiliation(s)
- Luping Yin
- Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA
| | - Dayu Lin
- Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA.
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4
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Phung T, Ramzan F, Monks DA. Hormone-dependent sexual responses of female mice in response to manual genital stimulation. Horm Behav 2023; 151:105338. [PMID: 36868148 DOI: 10.1016/j.yhbeh.2023.105338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 01/31/2023] [Accepted: 02/18/2023] [Indexed: 03/05/2023]
Abstract
Although copulatory behavior is thought to have a strong innate basis in mice, there is also clear evidence that sexual experience shapes its expression. Reinforcement of behavior through rewarding genital tactile stimulation is a primary candidate mechanism for this modification. In rats, manual tactile clitoral stimulation is rewarding only when it is temporally distributed, which is hypothesized to result from an innate preference for species-typical copulatory patterning. Here we test this hypothesis using mice, which have a temporal copulatory pattern which is distinctly less temporally distributed than that of rats. Female mice received manual clitoral stimulation which was either temporally continuous every second, or stimulation which was temporally distributed, occurring every 5 s, This pattern of stimulation was paired with environmental cues in a conditioned place preference apparatus to assess reward. Neural activation in response to this stimulation was evaluated by measuring FOS immunoreactivity. Results indicated that both temporal patterns of clitoral stimulation were rewarding, but that continuous stimulation better reproduced brain activation associated with sexual reward. Furthermore, continuous, but not distributed stimulation elicited a lordosis response in some females, and this response increased within and across days. Sexual reward, neural activation and lordosis resulting from tactile genital stimulation were eliminated by ovariectomy and restored with combined 17β-estradiol and progesterone treatment but not 17β-estradiol treatment alone. These observations are consistent with the hypothesis that sexual reward resulting from species-typical genital tactile stimulation has a permissive effect on copulatory behavior of female mice.
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Affiliation(s)
- Thanh Phung
- Department of Psychology, University of Toronto Mississauga, Canada; Department of Cell and Systems Biology, University of Toronto, Canada
| | - Firyal Ramzan
- Department of Psychology, University of Toronto Mississauga, Canada; Department of Biology, University of Waterloo, ON, Canada
| | - D Ashley Monks
- Department of Psychology, University of Toronto Mississauga, Canada; Department of Cell and Systems Biology, University of Toronto, Canada.
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5
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Bellofiore N, George E, Vollenhoven B, Temple-Smith P. Reproductive aging and menopause-like transition in the menstruating spiny mouse (Acomys cahirinus). Hum Reprod 2021; 36:3083-3094. [PMID: 34601586 DOI: 10.1093/humrep/deab215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/31/2021] [Indexed: 11/14/2022] Open
Abstract
STUDY QUESTION Does the naturally menstruating spiny mouse go through menopause? SUMMARY ANSWER Our study is the first to show a natural and gradual menopausal transition in a rodent. WHAT IS KNOWN ALREADY Age-related depletion of the human ovarian reserve (OvR) leads to menopause, the permanent cessation of menstruation and reproduction. Current rodent models of menopause are inappropriate for inferences of the human condition, as reproductive senescence is abrupt or induced through ovariectomy. The spiny mouse is the only confirmed rodent with a naturally occurring menstrual cycle. STUDY DESIGN, SIZE, DURATION Histological assessment of virgin spiny mice occurred in females aged 6 months (n = 14), 1 year (n = 7), 2 years (n = 13), 3 years (n = 9) and 4 years (n = 9). Endocrinology was assessed in a further 9 females per age group. Five animals per group were used for ovarian stereology with additional ovaries collected at prenatal Day 35 (n = 3), day of birth (n = 5), postnatal Days 35 (n = 5) and 100 (n = 5) and 15 months (n = 5). PARTICIPANTS/MATERIALS, SETTING, METHODS Morphological changes in the reproductive system were examined using hematoxylin and eosin stains. Proliferating cell nuclear antigen immunohistochemistry assessed endometrial proliferation and sex steroids estradiol and testosterone were assayed using commercial ELISA kits. MAIN RESULTS AND THE ROLE OF CHANCE The proportion of females actively cycling was 86% at 6 months, 71% at 1 year, 69% at 2 years, 56% at 3 years and 44% at 4 years. Uterine and ovarian weights declined steadily from 1 year in all groups and corresponded with loss of uterine proliferation (P < 0.01). Estradiol was significantly decreased at 1 and 2 years compared to 6-month-old females, before becoming erratic at 3 and 4 years, with no changes in testosterone across any age. Fully formed primordial follicles were observed in prenatal ovaries. Aging impacted on both OvR and growing follicle numbers (P < 0.001-0.0001). After the age of 3 years, the follicle decline rate increased more than 5-fold. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION This is a descriptive study in a novel research rodent whereby reagents validated for use in the spiny mouse were limited. WIDER IMPLICATIONS OF THE FINDINGS The gradual, rather than sudden, menopausal transition suggests that the spiny mouse is a more appropriate perimenopausal model than the current rodent models in which to examine the neuroendocrine pathways that encompass all hormonal interactions in the hypothalamic-pituitary-gonadal axis. The logistic, ethical and economic advantages of such a model may reduce our reliance on primates in menopause research and enable more thorough and invasive investigation than is possible in humans. STUDY FUNDING/COMPETING INTEREST(S) Hudson Institute is supported by the Victorian State Government Operational Infrastructure Scheme. The authors declare no competing interests.
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Affiliation(s)
- Nadia Bellofiore
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Obstetrics and Gynecology, Monash University, Clayton, VIC, Australia
| | - Evgenia George
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Obstetrics and Gynecology, Monash University, Clayton, VIC, Australia
| | - Beverley Vollenhoven
- Obstetrics and Gynecology, Monash University, Clayton, VIC, Australia.,Women's and Newborn Program, Monash Health, Clayton, VIC, Australia
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6
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Lough-Stevens M, Ghione CR, Urness M, Hobbs A, Sweeney CM, Dean MD. Male-derived copulatory plugs enhance implantation success in female Mus musculus. Biol Reprod 2021; 104:684-694. [PMID: 33355341 PMCID: PMC7962766 DOI: 10.1093/biolre/ioaa228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/09/2020] [Indexed: 12/11/2022] Open
Abstract
Among a wide diversity of sexually reproducing species, male ejaculates coagulate to form what has been termed a copulatory plug. A number of functions have been attributed to copulatory plugs, including the inhibition of female remating and the promotion of ejaculate movement. Here we demonstrate that copulatory plugs also influence the likelihood of implantation, which occurs roughly 4 days after copulation in mice. Using a bead transfer method to control for differences in ejaculate retention and fertilization rates, we show that implantation rates significantly drop among females mated to genetically engineered males incapable of forming plugs (because they lack functional transglutaminase 4, the main enzyme responsible for its formation). Surprisingly, this result does not correlate with differences in circulating progesterone levels among females, an important hormone involved in implantation. We discuss three models that connect male-derived copulatory plugs to implantation success, including the hypothesis that plugs contribute to a threshold amount of stimulation required for females to become receptive to implantation.
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Affiliation(s)
- Michael Lough-Stevens
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Caleb R Ghione
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Matthew Urness
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Adelaide Hobbs
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Colleen M Sweeney
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Matthew D Dean
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
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7
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Bellofiore N, Ellery SJ, Temple-Smith P, Evans J. Pseudopregnancy and reproductive cycle synchronisation cannot be induced using conventional methods in the spiny mouse (Acomys cahirinus). Reprod Fertil Dev 2021; 32:363-372. [PMID: 31839110 DOI: 10.1071/rd18506] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 07/28/2019] [Indexed: 01/05/2023] Open
Abstract
The menstruating spiny mouse is the first rodent identified to exhibit natural spontaneous decidualisation, cyclical endometrial shedding and regeneration. While the spiny mouse shares several primate-like characteristics in its reproductive biology, it has not been established whether pseudopregnancy can be induced or if its cycles can be synchronised as in non-human mammals. Here we describe attempts to induce pseudopregnancy and synchronisation of menstrual cycles (i.e. Whitten effect) in spiny mice. Virgin females (n=3-8 per group) underwent one of the following procedures to induce pseudopregnancy: daily vaginal lavage only (control), progesterone injection, mechanical stimulation of the cervix and sterile mating. A separate cohort was also exposed to male-soiled bedding to assess the Whitten effect. Pseudopregnancy was deemed successful if females presented with extended (>12 consecutive days) leukocytic vaginal cytology. No female from any method of induction met this criterion. In addition, the menstrual cycles of a group of six females could not be synchronised, nor immediate ovulation induced via exposure to male-soiled bedding. These responses indicate that the spiny mouse does not behave as a typical rodent. Like higher-order primates, the spiny mouse exhibits a relatively rare reproductive strategy, of failure to show pseudopregnancy or cyclical synchronisation. This is further endorsement of the use of this species as a versatile animal model for translational studies of menstruation and fertility.
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Affiliation(s)
- Nadia Bellofiore
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Vic. 3168, Australia; and Department of Obstetrics and Gynaecology, Monash University, Clayton, Vic. 3168, Australia; and Corresponding author.
| | - Stacey J Ellery
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Vic. 3168, Australia; and Department of Obstetrics and Gynaecology, Monash University, Clayton, Vic. 3168, Australia
| | - Peter Temple-Smith
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Vic. 3168, Australia
| | - Jemma Evans
- Centre for Reproductive Health, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Vic. 3168, Australia
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8
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Mating in the absence of fertilization promotes a growth-reproduction versus lifespan trade-off in female mice. Proc Natl Acad Sci U S A 2020; 117:15748-15754. [PMID: 32571943 DOI: 10.1073/pnas.2003159117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Trade-offs between growth, reproduction, and lifespan constrain animal life histories, leading to evolutionary diversification of life history cycles in different environments. In female mammals, gestation and lactation are expected to impose the major costs of reproduction, driving reproductive trade-offs, although mating also requires interactions with males that could themselves influence life history. Here we show that a male's presence by itself leads to lifelong alterations in life history in female mice. Housing C57BL/6J female mice with sterilized males early in life led to an increase in body weight, an effect that persisted across life even when females were later allowed to produce pups. We found that those females previously housed with sterile males also showed enhanced late-life offspring production when allowed to reproduce, indicating that earlier mating can influence subsequent fecundity. This effect was the opposite to that seen in females previously housed with intact males, which showed the expected trade-off between early-life and late-life reproduction. However, housing with a sterile male early in life came at a cost to lifespan, which was observed in the absence of females ever undergoing fertilization. Endocrinologically, mating also permanently reduced the concentration of circulating prolactin, a pituitary hormone influencing maternal care. Changes in hormone axes that influence reproduction could therefore help alter life history allocation in response to opposite-sex stimuli. Our results demonstrate that mating itself can increase growth and subsequent fecundity in mammals, and that responses to sexual stimuli could account for some lifespan trade-offs normally attributed to pregnancy and lactation.
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9
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Sexual experience with a known male modulates c-Fos expression in response to mating and male pheromone exposure in female mice. Physiol Behav 2020; 222:112906. [PMID: 32445810 DOI: 10.1016/j.physbeh.2020.112906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/25/2020] [Accepted: 04/03/2020] [Indexed: 11/24/2022]
Abstract
Sexually naïve female mice are not sexually receptive in their first mating opportunity. Four to five sexual encounters are needed to display high sexual receptivity as assessed by the lordosis reflex. The neuronal changes induced by sexual experience are not well understood. In this study, we evaluated if repeated sexual stimulation with the same male was associated with an increase in the neuronal activity evaluated by c-Fos expression in brain structures associated with the control of sexual behavior such as the accessory olfactory bulb (AOB), ventromedial hypothalamus (VMH), and the medial preoptic area (MPOA). Ovariectomized female mice were randomly distributed into three groups: sexually naïve (SN), with no prior sexual stimulation; sexually inexperienced (SI), with one prior mating session; and sexually experienced (SE), with six prior mating sessions. Females were primed with estradiol benzoate and progesterone once a week for 7 weeks. Neuronal activation in response to mating or soiled bedding was evaluated in the 7th week. Each group was subdivided into three subgroups: clean (exposure to clean bedding), male bedding (exposure to sawdust soiled with secretions from a male), or mating. Each female mated with her assigned male; in the exposure subgroup, soiled bedding was obtained from the male with whom she mated. Neuronal activity data showed that SE females had a higher c-Fos response in the VMH when they mated in comparison to females exposed to clean bedding. SI females that mated had a decrease c-Fos expression in the glomerular cell layer of the AOB, compared to females exposed to male bedding. The mitral cell layer showed a higher c-Fos response in SI females that mated in comparison to those exposed to male bedding. Comparisons between groups presented with the same stimulus indicate that SI females exposed to male bedding showed a decrease in c-Fos response in the mitral cell layer in comparison to SE and SN females. Correlation analysis demonstrated that the lordosis quotient from the last mating test correlated positively with the number of c-Fos-positive cells in the mitral cell layer in SE and SI groups. A similar correlation was found in the MPOA in SI females. Prior mating in female mice is required to increase sexual receptivity. Changes in the neuronal activity in the AOB and VMH may be involved in the neuronal plasticity induced by repeated sexual stimulation.
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10
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Phillipps HR, Yip SH, Grattan DR. Patterns of prolactin secretion. Mol Cell Endocrinol 2020; 502:110679. [PMID: 31843563 DOI: 10.1016/j.mce.2019.110679] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 12/11/2022]
Abstract
Prolactin is pleotropic in nature affecting multiple tissues throughout the body. As a consequence of the broad range of functions, regulation of anterior pituitary prolactin secretion is complex and atypical as compared to other pituitary hormones. Many studies have provided insight into the complex hypothalamic-pituitary networks controlling prolactin secretion patterns in different species using a range of techniques. Here, we review prolactin secretion in both males and females; and consider the different patterns of prolactin secretion across the reproductive cycle in representative female mammals with short versus long luteal phases and in seasonal breeders. Additionally, we highlight changes in the pattern of secretion during pregnancy and lactation, and discuss the wide range of adaptive functions that prolactin may have in these important physiological states.
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Affiliation(s)
- Hollian R Phillipps
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - Siew H Yip
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand.
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11
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Pavlicev M, Zupan AM, Barry A, Walters S, Milano KM, Kliman HJ, Wagner GP. An experimental test of the ovulatory homolog model of female orgasm. Proc Natl Acad Sci U S A 2019; 116:20267-20273. [PMID: 31570579 PMCID: PMC6789565 DOI: 10.1073/pnas.1910295116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The ovulatory homolog model of female orgasm posits that the neuro-endocrine mechanisms underlying female orgasm evolved from and are homologous to the mechanisms mediating copulation-induced ovulation in some mammals. This model predicts that pharmacological agents that affect human orgasm, such as fluoxetine, should also affect ovulation in animals with copulation-induced ovulation, such as rabbits. We tested this prediction by treating rabbits with daily doses of fluoxetine for 2 wk and found that fluoxetine treatment reduces the number of ovulations postcopulation by 30%. In a second experiment we tested whether this result was mediated by an effect on the brain or via peripheral serotonin functions. We treated animals with fluoxetine and induced ovulation with a single injection of human chorionic gonadotropin. In this experiment ovulation rate was nominally reduced by only 8%, which is statistically not significant. We conclude that the effect of fluoxetine on copulation-induced ovulation rate supports the ovulatory homolog model of female orgasm, suggesting that female orgasm has very deep evolutionary roots among the early eutherian mammals.
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Affiliation(s)
- Mihaela Pavlicev
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH 45267
- Department of Philosophy, University of Cincinnati, Cincinnati, OH 45221
- Center for Preterm Birth, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Andreja Moset Zupan
- Center for Preterm Birth, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Amanda Barry
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH 45267
| | - Savannah Walters
- Veterinary Services Surgical Core, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Kristin M Milano
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale Medical School, New Haven, CT 06510
| | - Harvey J Kliman
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale Medical School, New Haven, CT 06510
| | - Günter P Wagner
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale Medical School, New Haven, CT 06510;
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520
- Yale Systems Biology Institute, Yale University, West Haven, CT 06516
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12
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Pantier LK, Li J, Christian CA. Estrous Cycle Monitoring in Mice with Rapid Data Visualization and Analysis. Bio Protoc 2019; 9:e3354. [PMID: 32695847 DOI: 10.21769/bioprotoc.3354] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The estrous cycle provides a readout of reproductive health in female laboratory rodents, and estrous cycle stage can be an important physiological variable. Accurate assessment of estrous cycle stage is also important in producing timed pregnancies for developmental studies. Here, we provide a protocol for evaluation of estrous cycle stage through a minimally invasive procedure of acquiring cells lining the vaginal cavity and immediate microscopic visual assessment of these cells without drying or staining. When performed over several consecutive days, the pattern of progression through the four main stages of the estrous cycle, and disruptions to this pattern, can be determined. We also present software that enables more efficient cycle stage data analysis and pattern visualization. These protocols and tools will thus facilitate the incorporation of female animals in laboratory experiments and enhance the assessment of relationships between the reproductive cycle and overall physiology and behavior.
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Affiliation(s)
- Leanna K Pantier
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jiang Li
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Catherine A Christian
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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13
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Warren MR, Spurrier MS, Roth ED, Neunuebel JP. Sex differences in vocal communication of freely interacting adult mice depend upon behavioral context. PLoS One 2018; 13:e0204527. [PMID: 30240434 PMCID: PMC6150532 DOI: 10.1371/journal.pone.0204527] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/10/2018] [Indexed: 11/18/2022] Open
Abstract
Ultrasonic vocalizations (USVs) are believed to play a critical role in mouse communication. Although mice produce USVs in multiple contexts, signals emitted in reproductive contexts are typically attributed solely to the male mouse. Only recently has evidence emerged showing that female mice are also vocally active during mixed-sex interactions. Therefore, this study aimed to systematically quantify and compare vocalizations emitted by female and male mice as the animals freely interacted. Using an eight-channel microphone array to determine which mouse emitted specific vocalizations during unrestrained social interaction, we recorded 13 mixed-sex pairs of mice. We report here that females vocalized significantly less often than males during dyadic interactions, with females accounting for approximately one sixth of all emitted signals. Moreover, the acoustic features of female and male signals differed. We found that the bandwidths (i.e., the range of frequencies that a signal spanned) of female-emitted signals were smaller than signals produced by males. When examining how the frequency of each signal changed over time, the slopes of male-emitted signals decreased more rapidly than female signals. Further, we revealed notable differences between male and female vocal signals when the animals were performing the same behaviors. Our study provides evidence that a female mouse does in fact vocalize during interactions with a male and that the acoustic features of female and male vocalizations differ during specific behavioral contexts.
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Affiliation(s)
- Megan R. Warren
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Morgan S. Spurrier
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Eric D. Roth
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Joshua P. Neunuebel
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware, United States of America
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14
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André GI, Firman RC, Simmons LW. Phenotypic plasticity in genitalia: baculum shape responds to sperm competition risk in house mice. Proc Biol Sci 2018; 285:20181086. [PMID: 30051823 PMCID: PMC6053933 DOI: 10.1098/rspb.2018.1086] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 06/15/2018] [Indexed: 12/26/2022] Open
Abstract
Males are known to adjust their expenditure on testes growth and sperm production in response to sperm competition risk. Genital morphology can also contribute to competitive fertilization success but whether male genital morphology can respond plastically to the sperm competition environment has received little attention. Here, we exposed male house mice to two different sperm competition environments during their sexual development and quantified phenotypic plasticity in baculum morphology. The sperm competition environment generated plasticity in body growth. Males maturing under sperm competition risk were larger and heavier than males maturing under no sperm competition risk. We used a landmark-based geometric morphometric approach to measure baculum size and shape. Independent of variation in body size, males maintained under risk of sperm competition had a relatively thicker and more distally extended baculum bulb compared with males maintained under no sperm competition risk. Plasticity in baculum shape paralleled evolutionary responses to selection from sperm competition reported in previous studies of house mice. Our findings provide experimental evidence of socially mediated phenotypic plasticity in male genitalia.
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Affiliation(s)
- Gonçalo I André
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley 6009, Australia
| | - Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley 6009, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley 6009, Australia
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15
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Ladyman SR, Carter KM, Grattan DR. Energy homeostasis and running wheel activity during pregnancy in the mouse. Physiol Behav 2018; 194:83-94. [PMID: 29738792 DOI: 10.1016/j.physbeh.2018.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/13/2018] [Accepted: 05/04/2018] [Indexed: 01/08/2023]
Abstract
Pregnancy and lactation are metabolically challenging states, where the mother must supply all the energy requirements for the developing fetus and growing pups respectively. The aim of the current study was to characterize many aspects of energy homeostasis before and during pregnancy in the mouse, and to examine the role of voluntary activity on changes in energy expenditure during pregnancy. In a secondary aim, we evaluate measures of energy homeostasis during pregnancy in mice that successfully reared their litter or in mice that went on to abandon their litter, to determine if an impairment in pregnancy-induced adaptation of energy homeostasis might underlie the abandonment of pups soon after birth. During pregnancy, food intake was increased, characterized by increased meal size and duration but not number of meals per day. The duration of time spent inactive, predicted to indicate sleep behaviour, was increased both early and late in pregnancy compared to pre-pregnancy levels. Increased x + y beam breaks, as a measure of activity increased during pregnancy and this reflected an increase in ambulatory behaviour in mid pregnancy and an increase in non-ambulatory movement in late pregnancy. Energy expenditure, as measured by indirect calorimetry, increased across pregnancy, likely due to the growth and development of fetal tissue. There was also a dramatic reduction in voluntary wheel running as soon as the mice became pregnant. Compared with successful pregnancies and lactations, pregnancies where pups were abandoned soon after birth were associated with reduced body weight gain and an increase in running wheel activity at the end of pregnancy, but no difference in food intake or energy expenditure. Overall, during pregnancy there are multiple adaptations to change energy homeostasis, resulting in partitioning of provisions of energy to the developing fetus and storing energy for future metabolic demands.
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Affiliation(s)
- S R Ladyman
- Centre for Neuroendocrinology, Department of Anatomy School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
| | - K M Carter
- Centre for Neuroendocrinology, Department of Anatomy School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - D R Grattan
- Centre for Neuroendocrinology, Department of Anatomy School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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16
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Garrels W, Wedekind D, Wittur I, Freischmidt U, Korthaus D, Rülicke T, Dorsch M. Direct comparison of vasectomized males and genetically sterile Gapdhs knockout males for the induction of pseudopregnancy in mice. Lab Anim 2017; 52:365-372. [PMID: 29277131 DOI: 10.1177/0023677217748282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The laboratory mouse is the most used animal model in biomedical research. Several artificial reproductive techniques, such as revitalization of cryopreserved strains, rederivation after hygienic contaminations and the production of transgenic mouse models, require the transfer of preimplantation embryos to surrogate mothers. Pseudopregnancy is essential in recipient females and is induced by mating with sterile males. Commonly, surgically vasectomized males are used for this purpose. As an alternative, genetically modified mouse strains have been identified, in which homozygous infertile males are sexually active. Here, we investigated the suitability of genetically infertile Gapdhstm1Dao males under routine laboratory conditions with respect to plug rates, pregnancy rates and frequency of born offspring after embryo transfer. Our results showed no significant differences for these aspects between Gapdhstm1Dao and vasectomized CD2F1 males. In addition, we evaluated the efforts to obtain a defined number of sterile males either by breeding of sterile mutants or surgical vasectomy, and addressed the impact of both options on animal welfare. In conclusion, infertile males of the Gapdhstm1Dao line are a reliable alternative to vasectomized males for the induction of pseudopregnancy, and can contribute to the refinement of the procedure by avoiding surgical interventions.
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Affiliation(s)
- Wiebke Garrels
- 1 Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Dirk Wedekind
- 1 Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Isabell Wittur
- 1 Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Ulrike Freischmidt
- 1 Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Dirk Korthaus
- 2 Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Austria
| | - Thomas Rülicke
- 2 Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Austria
| | - Martina Dorsch
- 1 Institute for Laboratory Animal Science, Hannover Medical School, Germany
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17
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Schneider MR, Mangels R, Dean MD. The molecular basis and reproductive function(s) of copulatory plugs. Mol Reprod Dev 2016; 83:755-767. [PMID: 27518218 DOI: 10.1002/mrd.22689] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/10/2016] [Indexed: 12/12/2022]
Abstract
In many animals, male ejaculates coagulate to form what has been termed a copulatory plug, a structure that varies in size and shape but often fills and seals the female's reproductive tract. The first published observation of a copulatory plug in a mammal was made more than 160 years ago, and questions about its formation and role in reproduction continue to endear evolutionary and population geneticists, behavioral ecologists, and molecular, reproductive, and developmental biologists alike. Here, we review the current knowledge of copulatory plugs, focusing on rodents and asking two main questions: how is it formed and what does it do? An evolutionary biology perspective helps us understand the latter, potentially leading to insights into the selective regimes that have shaped the diversity of this structure. Mol. Reprod. Dev. 83: 755-767, 2016 © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Rachel Mangels
- Molecular and Computational Biology, University of Southern California, Los Angeles, California
| | - Matthew D Dean
- Molecular and Computational Biology, University of Southern California, Los Angeles, California.
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18
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Estrous cycle staging before mating led to increased efficiency in the production of pseudopregnant recipients without negatively affecting embryo transfer in mice. Theriogenology 2015; 85:813-821. [PMID: 26613855 DOI: 10.1016/j.theriogenology.2015.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 10/19/2015] [Accepted: 10/23/2015] [Indexed: 11/23/2022]
Abstract
The goal was to increase pseudopregnant mice production by estrous cycle staging by visual examination before pairing and to determine the effect of such pseudopregnant recipients on embryo transfer. To compare methods of estrous cycle staging over 14 days, groups consisted of 10 females in proestrus-estrus and 10 vasectomized males; group 1: only daily visual observation; group 2: daily visual observation and cytological examination on day 1; group 3: daily visual observation and daily cytological examination. The average time to first vaginal plug was 1.8 days in group 1, 2.7 days in group 2, and 3.2 days in group 3, whereas the average time between consecutive vaginal plugs was 9.2 days (group 1), 10 days (group 2), and 9.25 days (group 3). The average time between consecutive estrous cycles was 9.7 days (group 1), 11.8 days (group 2), and 9.4 days (group 3). The congruence between visual and cytological examination in determining proestrus-estrus in group 2 was 100% and that for the four stages in group 3 was 79% with a range of 44% to 100%. From 162 plug-positive females originally selected in proestrus-estrus, 49%, 30%, 19%, and 2% were plug-positive on Day 1, Day 2, Day 3, and Day 4, respectively, showing that pseudopregnant mice production was significantly increased on the first 2 days. From 192 plug-positive females originally selected randomly, these values were 31%, 21%, 35%, 10%, and 3% on d1, d2, d3, d4, and d5, respectively. No significant differences were observed between groups with respect to embryo transfers with fresh or cryopreserved embryos although the number of pups born per litter was higher in group A with fresh (7.57 vs. 6.39) and cryopreserved-thawed embryos (5.0 vs. 4.38). Furthermore, the sex ratio and the genotype of the pups were not significantly affected.
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19
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Mamrot J, Pangestu M, Walker D, Gardner DK, Dickinson H. Confirmed dioestrus in pseudopregnant mice using vaginal exfoliative cytology improves embryo transfer implantation rate. Reprod Biomed Online 2015; 31:538-43. [DOI: 10.1016/j.rbmo.2015.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/17/2015] [Accepted: 06/17/2015] [Indexed: 11/28/2022]
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20
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Guillou A, Romanò N, Steyn F, Abitbol K, Le Tissier P, Bonnefont X, Chen C, Mollard P, Martin AO. Assessment of lactotroph axis functionality in mice: longitudinal monitoring of PRL secretion by ultrasensitive-ELISA. Endocrinology 2015; 156:1924-30. [PMID: 25643154 DOI: 10.1210/en.2014-1571] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The pattern of prolactin (PRL) secretion depends on the physiological state. Due to insufficient detection sensitivity of existing assays, the precise description of these patterns in mice is lacking. We described an ultrasensitive ELISA assay that can detect mouse PRL in small fractions of whole blood, allowing longitudinal studies of PRL secretion profiles in freely moving mice. Over a 24-hour period, males displayed no oscillation in PRL levels, whereas virgin and lactating females showed large pulses. Peaks of PRL secretion reached 30-40 ng/mL in lactating female mice and rarely exceeded 10 ng/mL in virgin females. These pulses of PRL in lactating females were associated with suckling. The return of pups after an experimental 12-hour weaning induced a pulse of PRL release, reaching 100 ng/mL. This approach also enabled us to assess the inhibitory tone from hypothalamic dopamine neurons on PRL secretion. We used a dopamine D2 receptor antagonist to relieve pituitary lactotrophs from the tuberoinfundibular dopaminergic inhibitory tone and demonstrate a D2-induced PRL rise that can be used to evaluate both the secretory capacity of lactotrophs and the magnitude of the inhibitory tone on pituitary PRL release. We demonstrate that, although lactotroph function is altered to enhance chronic PRL output, their secretory response to acute stimulus is not modified during lactation and that chronic hyperprolactinemia is linked to a lower inhibitory tone. The combination of a sensitive PRL ELISA and administration of D2 receptor antagonist provide a unique opportunity to investigate the function and plasticity of the lactotroph axis in freely moving mice.
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Affiliation(s)
- Anne Guillou
- Unité Mixte de Recherche-5203 (A.G., N.R., K.A., X.B., P.M., A.O.M.), Centre National de la Recherche Scientifique, Institut de Génomique Fonctionnelle, INSERM (A.G., N.R., K.A., X.B., P.M., A.O.M.), Unité 661, and Unité Mixte de Recherche-5203 (A.G., N.R., K.A., X.B., P.M., A.O.M.), Universités de Montpellier 1 and 2, F-34000 Montpellier, France; School of Biomedical Sciences (F.S., C.C.), Faculty of Medicine and Biomedical Sciences, University of Queensland, St Lucia, Queensland 4072, Australia; and Centre for Integrative Physiology (P.L.T.), University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
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21
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Simmons LW, Firman RC. EXPERIMENTAL EVIDENCE FOR THE EVOLUTION OF THE MAMMALIAN BACULUM BY SEXUAL SELECTION. Evolution 2013; 68:276-83. [DOI: 10.1111/evo.12229] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/30/2013] [Indexed: 02/05/2023]
Affiliation(s)
- Leigh W. Simmons
- Centre for Evolutionary Biology; School of Animal Biology (M092); The University of Western Australia; Crawley 6009 Australia
| | - Renée C. Firman
- Centre for Evolutionary Biology; School of Animal Biology (M092); The University of Western Australia; Crawley 6009 Australia
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22
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McLean AC, Valenzuela N, Fai S, Bennett SAL. Performing vaginal lavage, crystal violet staining, and vaginal cytological evaluation for mouse estrous cycle staging identification. J Vis Exp 2012:e4389. [PMID: 23007862 PMCID: PMC3490233 DOI: 10.3791/4389] [Citation(s) in RCA: 256] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
A rapid means of assessing reproductive status in rodents is useful not only in the study of reproductive dysfunction but is also required for the production of new mouse models of disease and investigations into the hormonal regulation of tissue degeneration (or regeneration) following pathological challenge. The murine reproductive (or estrous) cycle is divided into 4 stages: proestrus, estrus, metestrus, and diestrus. Defined fluctuations in circulating levels of the ovarian steroids 17-β-estradiol and progesterone, the gonadotropins luteinizing and follicle stimulating hormones, and the luteotropic hormone prolactin signal transition through these reproductive stages. Changes in cell typology within the murine vaginal canal reflect these underlying endocrine events. Daily assessment of the relative ratio of nucleated epithelial cells, cornified squamous epithelial cells, and leukocytes present in vaginal smears can be used to identify murine estrous stages. The degree of invasiveness, however, employed in collecting these samples can alter reproductive status and elicit an inflammatory response that can confound cytological assessment of smears. Here, we describe a simple, non-invasive protocol that can be used to determine the stage of the estrous cycle of a female mouse without altering her reproductive cycle. We detail how to differentiate between the four stages of the estrous cycle by collection and analysis of predominant cell typology in vaginal smears and we show how these changes can be interpreted with respect to endocrine status.
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Affiliation(s)
- Ashleigh C McLean
- Department of Biochemistry, Microbiology and Immunology, Neural Regeneration Laboratory and Ottawa Institute of Systems Biology
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23
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Larsen CM, Grattan DR. Prolactin, neurogenesis, and maternal behaviors. Brain Behav Immun 2012; 26:201-9. [PMID: 21820505 DOI: 10.1016/j.bbi.2011.07.233] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 07/04/2011] [Accepted: 07/14/2011] [Indexed: 11/17/2022] Open
Abstract
Elevated prolactin during pregnancy increases neurogenesis in the subventricular zone of the lateral ventricle (SVZ) of the maternal brain. Evidence from our laboratory has shown that low prolactin in early pregnancy, and the consequent suppression of neurogenesis in the SVZ in the adult brain, is associated with increased postpartum anxiety and markedly impaired maternal behavior. Daughters of low prolactin mothers also display increased anxiety and a significant delay in the onset of puberty, which is associated with epigenetic changes in neuronal development (see Fig. 1). This suggests that, in rodents, low prolactin in early pregnancy exerts long-term effects that influence maternal mood postpartum, and offspring development. This mini-review aims to summarize the evidence showing that the prolactin-induced increase in SVZ neurogenesis during pregnancy underlies normal postpartum maternal interactions with pups.
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Affiliation(s)
- C M Larsen
- Centre for Neuroendocrinology, Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand.
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24
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Parker VJ, Menzies JRW, Douglas AJ. Differential changes in the hypothalamic-pituitary-adrenal axis and prolactin responses to stress in early pregnant mice. J Neuroendocrinol 2011; 23:1066-78. [PMID: 21824206 DOI: 10.1111/j.1365-2826.2011.02204.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Stress can cause pregnancy failure but it is unclear how the mother's neuroendocrine system responds to stress to impair mechanisms establishing implantation. We analysed stress-evoked hypothalamic-pituitary-adrenal (HPA) axis responses in early pregnant mice. HPA axis secretory responses to immune stress in early-mid pregnancy were strong and similar to that in virgins, although activation of hypothalamic vasopressin neurones, rather than corticotrophin-releasing hormone neurones, may be more important in the stress response in pregnancy. The site and mode of detrimental glucocorticoid action in pregnancy is not established. Because circulating prolactin is important for progesterone secretion and pregnancy establishment, we also hypothesised that stress negatively impacts on prolactin and its neuroendocrine control systems in early pregnant mice. Basal prolactin secretion was profoundly inhibited by either immune or fasting stress in early pregnancy. Prolactin release is inhibited by tonic dopamine release from tuberoinfundibular (TIDA) neurones. However, immune stress did not increase TIDA neurone activity in the median eminence in pregnant mice [measured by 3,4-dihydroxyphenylacetic acid (DOPAC) content and the DOPAC:dopamine ratio]. By contrast, both immune stress and fasting caused weak induction of Fos in TIDA neurones. However, Fos induction does not always reflect dopamine secretion. Taken together, the data suggest that the stress-evoked profound reduction in prolactin secretion does not involve substantially increased dopamine activity as anticipated. In pregnancy, there was also attenuated recruitment of parvocellular paraventricular nucleus neurones and increased activation of brainstem noradrenergic nuclei after immune stress, indicating that other mechanisms may be involved in the suppression of prolactin secretion. In summary, low prolactin and increased circulating glucocorticoids together may partly explain how a mother's endocrine system mediates stress-induced pregnancy failure.
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Affiliation(s)
- V J Parker
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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25
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Clapp C, de la Escalera GM. Peripheral regulation of prolactin by oxytocin: focus on "Systemic oxytocin induces a prolactin secretory rhythm via the pelvic nerve in ovariectomized rats". Am J Physiol Regul Integr Comp Physiol 2011; 301:R674-5. [PMID: 21715700 DOI: 10.1152/ajpregu.00331.2011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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Park CB, Dufort D. Nodal expression in the uterus of the mouse is regulated by the embryo and correlates with implantation. Biol Reprod 2011; 84:1103-10. [PMID: 21270430 DOI: 10.1095/biolreprod.110.087239] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Nodal, a transforming growth factor beta (TGFB) superfamily member, plays a critical role during early embryonic development. Recently, components of the Nodal signaling pathway were characterized in the human uterus and implicated in the tissue remodeling events during menstruation. Furthermore, the Nodal inhibitor, Lefty, was identified in the mouse endometrium during pregnancy, and its overexpression led to implantation failure. Nonetheless, the precise function and mechanism of Nodal signaling during pregnancy remains unclear. In order to elucidate the potential roles Nodal plays in these processes, we have generated a detailed profile of maternal Nodal expression in the mouse uterus throughout pregnancy. NODAL, although undetectable during the nonpregnant estrus cycle, was localized throughout the glandular epithelium of the endometrium during the peri-implantation period. Interestingly, Nodal expression generated a banding pattern along the proximal-distal axis of the uterine horn on Day 4.5 that directly correlated with blastocyst implantation. Embryo transfer experiments indicate the embryo regulates Nodal expression in the uterus and directs its expression at the time of implantation, restricting NODAL to the sites between implantation crypts. During the later stages of pregnancy, Nodal exhibits a dynamic expression profile that suggests a role in regulating the endometrial response to decidualization and associated trophoblast invasion.
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Affiliation(s)
- Craig B Park
- Division of Experimental Medicine, Royal Victoria Hospital, McGill University Health Centre, Montreal, Quebec, Canada
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27
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Larsen CM, Grattan DR. Prolactin-induced mitogenesis in the subventricular zone of the maternal brain during early pregnancy is essential for normal postpartum behavioral responses in the mother. Endocrinology 2010; 151:3805-14. [PMID: 20484459 DOI: 10.1210/en.2009-1385] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
High prolactin during pregnancy, which is essential for normal postpartum maternal behavior, increases neurogenesis in the subventricular zone of the lateral ventricle (SVZ) of the maternal brain. Because SVZ mitogenesis generates new olfactory neurons and may contribute to perception of novel odorants, we hypothesized that the prolactin-induced increase in SVZ mitogenesis during pregnancy might be important for normal maternal interactions with pups. To investigate this hypothesis, prolactin secretion was suppressed for 3 d early in pregnancy in mice, using a carefully timed dose of bromocriptine. The bromocriptine-induced reduction in prolactin prevented the normal increase in generation of neural progenitors in the SVZ of the maternal brain. Another group of bromocriptine-treated animals were allowed to continue their pregnancy until term, and then maternal behaviors were evaluated postpartum. Low prolactin during early pregnancy, and the consequent suppression of mitogenesis in the SVZ of the maternal brain, was subsequently followed by increased postpartum anxiety and markedly impaired maternal behavior. In another group of pregnant females, injections of the mitotic inhibitor methylazoxymethanol to specifically suppress neurogenesis in the mother during early pregnancy without affecting prolactin secretion also caused postpartum anxiety and impaired maternal behavior. These data demonstrate that prolactin-induced increase in generation of neural progenitors in the SVZ of the maternal brain during early pregnancy is required for normal expression of postpartum maternal behaviors.
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Affiliation(s)
- Caroline M Larsen
- Centre for Neuroendocrinology and Department of Anatomy and Structural Biology, University of Otago, New Zealand
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28
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Baby on board: do responses to stress in the maternal brain mediate adverse pregnancy outcome? Front Neuroendocrinol 2010; 31:359-76. [PMID: 20546772 DOI: 10.1016/j.yfrne.2010.05.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/17/2010] [Accepted: 05/18/2010] [Indexed: 02/02/2023]
Abstract
Stress and adverse environmental surroundings result in suboptimal conditions in a pregnant mother such that she may experience poor pregnancy outcome including complete pregnancy failure and preterm labor. Furthermore her developing baby is at risk of adverse programming, which confers susceptibility to long term ill health. While some mechanisms at the feto-maternal interface underlying these conditions are understood, the underlying cause for their adverse adaptation is often not clear. Progesterone plays a key role at many levels, including control of neuroendocrine responses to stress, procuring the required immune balance and controlling placental and decidual function, and lack of progesterone can explain many of the unwanted consequences of stress. How stress that is perceived by the mother inhibits progesterone secretion and action is beginning to be investigated. This overview of maternal neuroendocrine responses to stress throughout pregnancy analyses how they interact to compromise progesterone secretion and precipitate undesirable effects in mother and offspring.
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