1
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Li M. Is melanin-concentrating hormone in the medial preoptic area a signal for the decline of maternal care in late postpartum? Front Neuroendocrinol 2024; 75:101155. [PMID: 39222798 DOI: 10.1016/j.yfrne.2024.101155] [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: 07/08/2024] [Revised: 08/28/2024] [Accepted: 08/30/2024] [Indexed: 09/04/2024]
Abstract
This manuscript proposes that melanin-concentrating hormone (MCH) in the medial preoptic area (MPOA) is an neurochemical signal evolved to trigger the declining process of maternal care. MCH in the MPOA appears only after parturition and is progressively increased with the progression of lactation, while maternal behavior declines progressively. Intra-MPOA injection of MCH decreases active maternal responses. MCH is also highly responsive to infant characteristics and maternal condition. Behavioral changes induced by MCH in late postpartum period are conducive to the decline of infant-directed maternal behavior. The MPOA MCH system may mediate the maternal behavior decline by suppressing the maternal approach motivation and/or increasing maternal withdrawal via its inhibitory action onto the mesolimbic dopamine D1/D2 receptors and its stimulating action on serotonin 5-HT2C receptors in the ventral tegmental area. Research into the MCH maternal effects will enhance our understanding of the neurochemical mechanisms underlying the maternal behavior decline.
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Affiliation(s)
- Ming Li
- Department of Psychology, Nanjing University, Nanjing 210023, China.
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2
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Li M. Roadmap for maternal behavior research in domestic dogs: lessons from decades of laboratory rodent work. Front Vet Sci 2024; 11:1394201. [PMID: 38993275 PMCID: PMC11236756 DOI: 10.3389/fvets.2024.1394201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 06/12/2024] [Indexed: 07/13/2024] Open
Abstract
Maternal behavior research in laboratory rats has revealed important behavioral and neurobiological mechanisms governing the onset, maintenance and decline of maternal behavior. However, the extent to which these mechanisms are evolutionarily conserved across species is less clear. This manuscript proposes that examining these mechanisms in dogs may be a viable approach to test their generality and help bridge the gap between rodent and human research, as domestic dogs show greater individual differences and exhibit more human-like maternal characteristics than rodents. These aspects represent advantages over rodent models, which in turn allow systems biological approaches not available in rodents. Additionally, domestic dogs share similar social environments with humans, suffer from the same mental disorders as humans, and can be treated with the same medications. This paper begins with a summary of key findings and theoretical developments from decades of rat maternal behavior research, followed by a literature review of the extant maternal behavior research on dogs and related methodology, highlighting the unique behavioral characteristics of dog maternal behavior and similarities and differences from rat maternal behavior. Finally, several knowledge gaps in dog maternal behavior research, as well as the future research in this area is discussed. It concludes that research on dog maternal behavior will not only advance our understanding of the universality of the neurobiological and behavioral mechanisms in maternal behavior, but also improve our understanding of risk factors associated with postpartum mental disorders.
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Affiliation(s)
- Ming Li
- Department of Psychology, Nanjing University, Nanjing, China
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3
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Mykins M, Bridges B, Jo A, Krishnan K. Multidimensional Analysis of a Social Behavior Identifies Regression and Phenotypic Heterogeneity in a Female Mouse Model for Rett Syndrome. J Neurosci 2024; 44:e1078232023. [PMID: 38199865 PMCID: PMC10957218 DOI: 10.1523/jneurosci.1078-23.2023] [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: 06/09/2023] [Revised: 11/01/2023] [Accepted: 11/17/2023] [Indexed: 01/12/2024] Open
Abstract
Regression is a key feature of neurodevelopmental disorders such as autism spectrum disorder, Fragile X syndrome, and Rett syndrome (RTT). RTT is caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). It is characterized by an early period of typical development with subsequent regression of previously acquired motor and speech skills in girls. The syndromic phenotypes are individualistic and dynamic over time. Thus far, it has been difficult to capture these dynamics and syndromic heterogeneity in the preclinical Mecp2-heterozygous female mouse model (Het). The emergence of computational neuroethology tools allows for robust analysis of complex and dynamic behaviors to model endophenotypes in preclinical models. Toward this first step, we utilized DeepLabCut, a marker-less pose estimation software to quantify trajectory kinematics and multidimensional analysis to characterize behavioral heterogeneity in Het in the previously benchmarked, ethologically relevant social cognition task of pup retrieval. We report the identification of two distinct phenotypes of adult Het: Het that display a delay in efficiency in early days and then improve over days like wild-type mice and Het that regress and perform worse in later days. Furthermore, regression is dependent on age and behavioral context and can be detected in the initial days of retrieval. Together, the novel identification of two populations of Het suggests differential effects on neural circuitry, opens new avenues to investigate the underlying molecular and cellular mechanisms of heterogeneity, and designs better studies for stratifying therapeutics.
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Affiliation(s)
- Michael Mykins
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Benjamin Bridges
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Angela Jo
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Keerthi Krishnan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
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4
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Lv Z, Li L, Li Y, Zhang L, Guo X, Huang C, Hou W, Qu Y, Liu L, Li Y, He Z, Tai F. Involvement of Serotonergic Projections from the Dorsal Raphe to the Medial Preoptic Area in the Regulation of the Pup-Directed Paternal Response of Male Mandarin Voles. Int J Mol Sci 2023; 24:11605. [PMID: 37511364 PMCID: PMC10380723 DOI: 10.3390/ijms241411605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/11/2023] [Accepted: 07/15/2023] [Indexed: 07/30/2023] Open
Abstract
Male mammals display different paternal responses to pups, either attacking or killing the young offspring, or contrastingly, caring for them. The neural circuit mechanism underlying the between-individual variation in the pup-directed responsiveness of male mammals remains unclear. Monogamous mandarin voles were used to complete the present study. The male individuals were identified as paternal and infanticidal voles, according their behavioral responses to pups. It was found that the serotonin release in the medial preoptic area (MPOA), as well as the serotonergic neuron activity, significantly increased upon licking the pups, but showed no changes after attacking the pups, as revealed by the in vivo fiber photometry of the fluorescence signal from the 5-HT 1.0 sensor and the calcium imaging indicator, respectively. It was verified that the 5-HTergic neural projections to the MPOA originated mainly from the ventral part of the dorsal raphe (vDR). Furthermore, the chemogenetic inhibition of serotonergic projections from the vDR to the MPOA decreased the paternal behaviors and shortened the latency to attack the pups. In contrast, the activation of serotonergic neurons via optogenetics extended the licking duration and inhibited infanticide. Collectively, these results elucidate that the serotonergic projections from the vDR to the MPOA, a previously unrecognized pathway, regulate the paternal responses of virgin male mandarin voles to pups.
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Affiliation(s)
- Zijian Lv
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Lu Li
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Yin Li
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Lizi Zhang
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Xing Guo
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Caihong Huang
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Wenjuan Hou
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Yishan Qu
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Limin Liu
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Yitong Li
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Zhixiong He
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
| | - Fadao Tai
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China
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5
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Unroe KA, Maltman JL, Shupe EA, Clinton SM. Disrupted serotonin system development via early life antidepressant exposure impairs maternal care and increases serotonin receptor expression in adult female offspring. Dev Psychobiol 2022; 64:e22292. [PMID: 35748633 DOI: 10.1002/dev.22292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 11/11/2022]
Abstract
Manipulating serotonin (5-HT) levels in the developing brain elicits a range of effects on brain function and behavior. For example, early-life exposure to selective 5-HT reuptake inhibitor (SSRI) antidepressants disrupts dorsal raphe function and triggers aberrant adult behaviors such as increased passive stress coping and anhedonia. However, much less is understood about how alterations in 5-HT signaling in early life impact outcomes in female offspring, including critical social functions such as maternal care. The present study shows that early-life SSRI exposure disrupts adult female offspring's maternal behavior. Pregnant/postpartum female Sprague-Dawley rats were treated with the SSRI citalopram in drinking water or provided regular tap water as control. Female offspring were raised to adulthood and mated with treatment-naïve males. Following parturition, we observed maternal behavior during portions of the light and dark phases of postnatal days (P)1-14. Relative to controls, dams with a history of early-life SSRI exposure exhibited decreased maternal care, including diminished arched-back nursing, reduced licking and grooming of pups, and increased behavioral inconsistency. Brains were collected from dams with and without a history of early-life SSRI exposure to measure relative mRNA expression of select 5-HT receptor transcripts (5HTR1A, -1B, -2A, -2C) in regions involved in maternal care. Early-life SSRI exposure augmented expression of 5-HTR1A in the medial preoptic area and 5-HTR1B, 5-HTR2A, and 5-HTR2C in the prefrontal cortex. These results demonstrate that early alterations to 5-HT signaling through SSRI exposure may disrupt nurturing parental behaviors and 5-HT receptor expression in affected female rat offspring.
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Affiliation(s)
- Keaton A Unroe
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA.,Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Jessica L Maltman
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Elizabeth A Shupe
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA.,Neuroscience Graduate Program, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Sarah M Clinton
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
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6
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Grieb ZA, Lonstein JS. Oxytocin interactions with central dopamine and serotonin systems regulate different components of motherhood. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210062. [PMID: 35858105 PMCID: PMC9272149 DOI: 10.1098/rstb.2021.0062] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 01/09/2022] [Indexed: 08/31/2023] Open
Abstract
The role of oxytocin in maternal caregiving and other postpartum behaviours has been studied for more than five decades. How oxytocin interacts with other neurochemical systems to enact these behavioural changes, however, is only slowly being elucidated. The best-studied oxytocin-neurotransmitter interaction is with the mesolimbic dopamine system, and this interaction is essential for maternal motivation and active caregiving behaviours such as retrieval of pups. Considerably less attention has been dedicated to investigating how oxytocin interacts with central serotonin to influence postpartum behaviour. Recently, it has become clear that while oxytocin-dopamine interactions regulate the motivational and pup-approach aspects of maternal caregiving behaviours, oxytocin-serotonin interactions appear to regulate nearly all other aspects including postpartum nursing, aggression, anxiety-like behaviour and stress coping strategy. Collectively, oxytocin's interactions with central dopamine and serotonin systems are thus critical for the entire suite of behavioural adaptations exhibited in the postpartum period, and these sites of interaction are potential pharmacological targets for where oxytocin could help to ameliorate deficits in maternal caregiving and poor postpartum mental health. This article is part of the theme issue 'Interplays between oxytocin and other neuromodulators in shaping complex social behaviours'.
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Affiliation(s)
- Zachary A. Grieb
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Joseph S. Lonstein
- Psychology Department, Michigan State University, East Lansing, MI 48824, USA
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7
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Pawluski JL, Hoekzema E, Leuner B, Lonstein JS. Less can be more: Fine tuning the maternal brain. Neurosci Biobehav Rev 2022; 133:104475. [PMID: 34864004 PMCID: PMC8807930 DOI: 10.1016/j.neubiorev.2021.11.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/18/2021] [Accepted: 11/30/2021] [Indexed: 02/03/2023]
Abstract
PAWLUSKI, J.L., Hoekzema, E., Leuner, B., and Lonstein, J.S. Less can be more: Fine tuning the maternal brain. NEUROSCI BIOBEHAV REV (129) XXX-XXX, 2022. Plasticity in the female brain across the lifespan has recently become a growing field of scientific inquiry. This has led to the understanding that the transition to motherhood is marked by some of the most significant changes in brain plasticity in the adult female brain. Perhaps unexpectedly, plasticity occurring in the maternal brain often involves a decrease in brain volume, neurogenesis and glial cell density that presumably optimizes caregiving and other postpartum behaviors. This review summarizes what we know of the 'fine-tuning' of the female brain that accompanies motherhood and highlights the implications of these changes for maternal neurobehavioral health. The first part of the review summarizes structural and functional brain changes in humans during pregnancy and postpartum period with the remainder of the review focusing on neural and glial plasticity during the peripartum period in animal models. The aim of this review is to provide a clear understanding of when 'less is more' in maternal brain plasticity and where future research can focus to improve our understanding of the unique brain plasticity occurring during matrescence.
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Affiliation(s)
- Jodi L. Pawluski
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail), UMR_S 1085, F-35000, Rennes, France.,Corresponding author: Jodi L. Pawluski, University of Rennes 1, Irset (Institut de Recherche en Santé, Environnement et Travail), UMR_S 1085, F-35000, Rennes, France.
| | - Elseline Hoekzema
- Brain and Development Laboratory, Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, The Netherlands.,Hoekzema Lab, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Benedetta Leuner
- The Ohio State University, Department of Psychology & Department of Neuroscience Columbus, OH, USA
| | - Joseph S. Lonstein
- Neuroscience Program & Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
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8
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Grieb ZA, Ford EG, Yagan M, Lau BYB, Manfredsson FP, Krishnan K, Lonstein JS. Oxytocin receptors in the midbrain dorsal raphe are essential for postpartum maternal social and affective behaviors. Psychoneuroendocrinology 2021; 131:105332. [PMID: 34182251 PMCID: PMC8405581 DOI: 10.1016/j.psyneuen.2021.105332] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 06/07/2021] [Accepted: 06/15/2021] [Indexed: 01/23/2023]
Abstract
Oxytocin receptors (OTRs) in the midbrain dorsal raphe (DR; the source of most forebrain serotonin) have recently been identified as a potential pharmacological target for treating numerous psychiatric disorders. However, almost all research on this topic has been conducted on males and the role of DR OTRs in female social and affective behaviors is mostly unknown. This may be particularly relevant during early motherhood, which is a time of high endogenous oxytocin signaling, but also a time of elevated risk for psychiatric dysfunction. To investigate whether OTRs in the DR are necessary for postpartum female social and affective behaviors, we constructed and then injected into the DR an adeno-associated virus permanently expressing an shRNA targeting OTR mRNA. We then observed a suite of social and affective behaviors postpartum. OTR knockdown in the maternal DR led to pup loss after parturition, decreased nursing, increased aggression, and increased behavioral despair. These effects of OTR knockdown in the DR may be due to disrupted neuroplasticity in the primary somatosensory cortex (S1), which mediates maternal sensitivity to the tactile cues from young, as we found significantly more plasticity-restricting perineuronal nets (PNNs) in the S1 rostral barrel field and fewer PNNs in the caudal barrel field of OTR-knockdown mothers. These results demonstrate that OTRs in the midbrain DR are essential for postpartum maternal social and affective behaviors, are involved in postpartum cortical plasticity, and suggest that pharmacotherapies targeting OTRs in the DR could be effective treatments for some peripartum affective disorders.
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Affiliation(s)
- Zachary A Grieb
- Neuroscience Program, Michigan State University, 108 Giltner Hall, East Lansing, MI 48824, USA.
| | - Emma G Ford
- Neuroscience Program, Michigan State University, 108 Giltner Hall, East Lansing, MI 48824, USA
| | - Mahircan Yagan
- Deparment of Biochemistry & Cellular and Molecular Biology, University of Tennessee, 1311 Cumberland Avenue, Knoxville, TN 37996, USA
| | - Billy Y B Lau
- Deparment of Biochemistry & Cellular and Molecular Biology, University of Tennessee, 1311 Cumberland Avenue, Knoxville, TN 37996, USA
| | - Fredric P Manfredsson
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI 49503, USA
| | - Keerthi Krishnan
- Deparment of Biochemistry & Cellular and Molecular Biology, University of Tennessee, 1311 Cumberland Avenue, Knoxville, TN 37996, USA
| | - Joseph S Lonstein
- Neuroscience Program, Michigan State University, 108 Giltner Hall, East Lansing, MI 48824, USA
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9
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Babicola L, Ventura R, D'Addario SL, Ielpo D, Andolina D, Di Segni M. Long term effects of early life stress on HPA circuit in rodent models. Mol Cell Endocrinol 2021; 521:111125. [PMID: 33333214 DOI: 10.1016/j.mce.2020.111125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/23/2020] [Accepted: 12/10/2020] [Indexed: 01/06/2023]
Abstract
Adaptation to environmental challenges represents a critical process for survival, requiring the complex integration of information derived from both external cues and internal signals regarding current conditions and previous experiences. The Hypothalamic-pituitary-adrenal axis plays a central role in this process inducing the activation of a neuroendocrine signaling cascade that affects the delicate balance of activity and cross-talk between areas that are involved in sensorial, emotional, and cognitive processing such as the hippocampus, amygdala, Prefrontal Cortex, Ventral Tegmental Area, and dorsal raphe. Early life stress, especially early critical experiences with caregivers, influences the functional and structural organization of these areas, affects these processes in a long-lasting manner and may result in long-term maladaptive and psychopathological outcomes, depending on the complex interaction between genetic and environmental factors. This review summarizes the results of studies that have modeled this early postnatal stress in rodents during the first 2 postnatal weeks, focusing on the long-term effects on molecular and structural alteration in brain areas involved in Hypothalamic-pituitary-adrenal axis function. Moreover, a brief investigation of epigenetic mechanisms and specific genetic targets mediating the long-term effects of these early environmental manipulations and at the basis of differential neurobiological and behavioral effects during adulthood is provided.
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Affiliation(s)
- Lucy Babicola
- Dept. of Psychology and Center "Daniel Bovet", Sapienza University, 00184, Rome, Italy; IRCCS Fondazione Santa Lucia, Via Del Fosso di Fiorano, 64, 00143, Rome, Italy
| | - Rossella Ventura
- Dept. of Psychology and Center "Daniel Bovet", Sapienza University, 00184, Rome, Italy; IRCCS Fondazione Santa Lucia, Via Del Fosso di Fiorano, 64, 00143, Rome, Italy.
| | - Sebastian Luca D'Addario
- Dept. of Psychology and Center "Daniel Bovet", Sapienza University, 00184, Rome, Italy; IRCCS Fondazione Santa Lucia, Via Del Fosso di Fiorano, 64, 00143, Rome, Italy; Behavioral Neuroscience PhD Programme, Sapienza University, Piazzale Aldo Moro 5, 00184, Rome, Italy
| | - Donald Ielpo
- Dept. of Psychology and Center "Daniel Bovet", Sapienza University, 00184, Rome, Italy; IRCCS Fondazione Santa Lucia, Via Del Fosso di Fiorano, 64, 00143, Rome, Italy; Behavioral Neuroscience PhD Programme, Sapienza University, Piazzale Aldo Moro 5, 00184, Rome, Italy
| | - Diego Andolina
- Dept. of Psychology and Center "Daniel Bovet", Sapienza University, 00184, Rome, Italy; IRCCS Fondazione Santa Lucia, Via Del Fosso di Fiorano, 64, 00143, Rome, Italy
| | - Matteo Di Segni
- IRCCS Fondazione Santa Lucia, Via Del Fosso di Fiorano, 64, 00143, Rome, Italy.
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10
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Grieb ZA, Lonstein JS. Oxytocin receptor expression in the midbrain dorsal raphe is dynamic across female reproduction in rats. J Neuroendocrinol 2021; 33:e12926. [PMID: 33427399 DOI: 10.1111/jne.12926] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 12/29/2022]
Abstract
Central oxytocin receptor (OTR) expression is extremely sensitive to circulating steroid hormones and OTRs influence many of the neurobehavioural adaptations associated with female reproduction (e.g., postpartum caregiving, aggression, cognition, affective responses). Changes in central OTR expression across female reproduction have often been studied, but almost all of such research has focused on the forebrain, ignoring hormone-sensitive midbrain sites such as the serotonergic dorsal raphe (DR) that are also critical for postpartum behaviours. To investigate the effects of female reproductive state on OTRs in the DR, we first used autoradiography to examine OTR binding across four female reproductive states in laboratory rats: dioestrous virgin, pregnancy day 10, the day of parturition and postpartum day 7. OTR binding in the rostral DR (but not other DR subregions) was approximately 250% higher in parturient rats compared to dioestrous virgins and dropped back down to virgin levels by postpartum day 7. Given the chemical heterogeneity of the DR, we then examined OTR expression in the three most abundant neuronal phenotypes of the DR (i.e., serotonin, GABA and dopamine) in dioestrous virgins and recently parturient females. Using dual-label immunohistochemistry and in situ hybridisation, we found that twice as many dopaminergic cells in the parturient rostral DR contained OTR immunoreactivity compared to that found in virgins. On the other hand, mothers had fewer rostral DR GABAergic cells expressing OTRs than did virgins. OTR expression in serotonin cells did not differ between the two groups. Overall, these results suggest that the rostral subregion of the midbrain DR is uniquely sensitive to oxytocin around the time of parturition, with subpopulations of cells that become more sensitive (i.e., dopamine), less sensitive (i.e., GABA) and show no change (i.e., serotonin) to this neuropeptide. This dynamic OTR signalling in the female DR may help drive the numerous behavioural changes across female reproduction that are necessary for successful motherhood.
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Affiliation(s)
- Zachary A Grieb
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Joseph S Lonstein
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
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11
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Sex-Specific Role for Dopamine Receptor D2 in Dorsal Raphe Serotonergic Neuron Modulation of Defensive Acoustic Startle and Dominance Behavior. eNeuro 2020; 7:ENEURO.0202-20.2020. [PMID: 33214315 PMCID: PMC7768286 DOI: 10.1523/eneuro.0202-20.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/19/2020] [Accepted: 11/09/2020] [Indexed: 11/27/2022] Open
Abstract
Brain networks underlying states of social and sensory alertness are normally adaptive, influenced by serotonin and dopamine (DA), and abnormal in neuropsychiatric disorders, often with sex-specific manifestations. Underlying circuits, cells, and molecules are just beginning to be delineated. Implicated is a subtype of serotonergic neuron denoted Drd2-Pet1, distinguished by expression of the type-2 DA receptor (Drd2) gene, inhibited cell-autonomously by DRD2 agonism in slice, and, when constitutively silenced in male mice, affects levels of defensive and exploratory behaviors (Niederkofler et al., 2016). Unknown has been whether DRD2 signaling in these Pet1 neurons contributes to their capacity for shaping defensive behaviors. To address this, we generated mice in which Drd2 gene sequences were deleted selectively in Pet1 neurons. We found that Drd2Pet1-CKO males, but not females, demonstrated increased winning against sex-matched controls in a social dominance assay. Drd2Pet1-CKO females, but not males, exhibited blunting of the acoustic startle response, a protective, defensive reflex. Indistinguishable from controls were auditory brainstem responses (ABRs), locomotion, cognition, and anxiety-like and depression-like behaviors. Analyzing wild-type Drd2-Pet1 neurons, we found sex-specific differences in the proportional distribution of axonal collaterals, in action potential (AP) duration, and in transcript levels of Gad2, important for GABA synthesis. Drd2Pet1-CKO cells displayed sex-specific differences in the percentage of cells harboring Gad2 transcripts. Our results suggest that DRD2 function in Drd2-Pet1 neurons is required for normal defensive/protective behaviors in a sex-specific manner, which may be influenced by the identified sex-specific molecular and cellular features. Related behaviors in humans too show sex differences, suggesting translational relevance.
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12
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Nordman J, Li Z. The Dorsal Raphe Regulates the Duration of Attack through the Medial Orbitofrontal Cortex and Medial Amygdala. eNeuro 2020; 7:ENEURO.0331-20.2020. [PMID: 33055195 PMCID: PMC7665904 DOI: 10.1523/eneuro.0331-20.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/21/2020] [Accepted: 09/25/2020] [Indexed: 12/20/2022] Open
Abstract
The dorsal raphe (DR) is an evolutionarily conserved brain structure that is involved in aggressive behavior. It projects onto numerous cortical and limbic areas underlying attack behavior. The specific neurocircuit through which the DR regulates aggression, however, is largely unclear. In this study we show that DR neurons expressing CaMKIIα are activated by attack behavior in mice. These neurons project to the medial aspect of the orbitofrontal cortex (OFC; MeOC) and the medial amygdala (MeA), two key regions within the neural circuit known to control aggressive behavior. Using an in vivo optogenetic approach, we show that attack bouts are shortened by inhibiting CaMKIIα+ neurons in the DR and their axons at the MeOC and prolonged by stimulating the DR-MeOC axons during an attack. By contrast, stimulating the axons of CaMKIIα+ DR neurons at the MeA shortens attack. Notably, neither the DR-MeOC or DR-MeA pathway initiates attack when stimulated. These results indicate that the DR-MeOC and DR-MeA pathways regulate the duration of attack behavior in opposite directions, revealing a circuit mechanism for the control of attack by the DR.
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Affiliation(s)
- Jacob Nordman
- Section on Synapse Development Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892
| | - Zheng Li
- Section on Synapse Development Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892
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13
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Psychological and neurobiological mechanisms underlying the decline of maternal behavior. Neurosci Biobehav Rev 2020; 116:164-181. [PMID: 32569707 DOI: 10.1016/j.neubiorev.2020.06.009] [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: 02/25/2020] [Revised: 05/27/2020] [Accepted: 06/05/2020] [Indexed: 11/23/2022]
Abstract
The maternal behavior decline is important for the normal development of the young and the wellbeing of the mother. This paper reviews limited research on the factors and mechanisms involved in the rat maternal behavior decline and proposes a multi-level model. Framed in the parent-offspring conflict theory (an ultimate cause) and the approach-withdrawal model (a proximate cause), the maternal behavior decline is viewed as an active and effortful process, reflecting the dynamic interplay between the mother and her offspring. It is instigated by the waning of maternal motivation, coupled with the increased maternal aversion by the mother in responding to the changing sensory and motoric patterns of pup stimuli. In the decline phase, the neural circuit that mediates the inhibitory ("withdrawal") responses starts to increase activity and gain control of behavioral outputs, while the excitatory ("approach") maternal neural circuit is being inhibited or reorganized. Various hormones and certain monoamines may play a critical role in tipping the balance between the excitatory and inhibitory neural circuits to synchronize the mother-infant interaction.
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14
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Gao J, Nie L, Li Y, Li M. Serotonin 5-HT2A and 5-HT2C receptors regulate rat maternal behavior through distinct behavioral and neural mechanisms. Neuropharmacology 2020; 162:107848. [DOI: 10.1016/j.neuropharm.2019.107848] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 10/18/2019] [Accepted: 11/06/2019] [Indexed: 01/24/2023]
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15
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Grieb ZA, Ragan CM. The effects of perinatal SSRI exposure on anxious behavior and neurobiology in rodent and human offspring. Eur Neuropsychopharmacol 2019; 29:1169-1184. [PMID: 31427116 DOI: 10.1016/j.euroneuro.2019.07.239] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/10/2019] [Accepted: 07/27/2019] [Indexed: 12/22/2022]
Abstract
While the postpartum period is typically associated with increased positive affect, many women will develop a depressive- or anxiety-related disorder during this time, which can degrade the mother-infant bond and lead to detrimental consequences for the infant. Given the potential for negative consequences, effective treatments have been critical, with selective serotonin reuptake inhibitors (SSRIs) being the most commonly-prescribed pharmaceutical agents to treat postpartum depression and anxiety. However, SSRIs can readily cross the placenta and are present in breast milk, so they might, therefore, unintentionally interact with the developing fetus/infant. There is already experimental evidence that perinatal SSRI exposure has a number of long-term effects on offspring, but this review focuses on the current literature examining the timing and consequences of perinatal SSRI exposure specifically on anxiety-like behaviors in rodents and humans, with an emphasis on the anxiety-related brain regions of the amygdala and hippocampus. This review also discusses discrepancies between the rodent and human literatures and how they might inform future studies. Finally, some key factors to consider when examining the role of perinatal SSRIs on offspring anxiety will be discussed, such as the duration of SSRI exposure and the potential neuroprotective effects of SSRIs. Given the extensive prescribing of SSRIs, the potential health consequences of perinatal SSRI exposure, and the discrepancies in the literature, it will be necessary to critically examine the factors underlying offspring anxiety outcomes.
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Affiliation(s)
- Z A Grieb
- Neuroscience Institute, 880 Petit Science Center, Georgia State University, Atlanta, GA 30303, United States.
| | - C M Ragan
- Department of Psychology, Library Student Faculty Building, Room 63, Purdue University Northwest, Westville, IN 46391, United States
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16
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Adidharma W, Deats SP, Ikeno T, Lipton JW, Lonstein JS, Yan L. Orexinergic modulation of serotonin neurons in the dorsal raphe of a diurnal rodent, Arvicanthis niloticus. Horm Behav 2019; 116:104584. [PMID: 31445011 PMCID: PMC6885537 DOI: 10.1016/j.yhbeh.2019.104584] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/02/2019] [Accepted: 08/20/2019] [Indexed: 01/22/2023]
Abstract
The hypothalamic neuropeptide, orexin (or hypocretin), is implicated in numerous physiology and behavioral functions, including affective states such as depression and anxiety. The underlying mechanisms and neural circuits through which orexin modulates affective responses remain unclear. The objective of the present study was to test the hypothesis that the serotonin (5-HT) system of the dorsal raphe nucleus (DRN) is a downstream target through which orexin potentially manifests its role in affective states. Using a diurnal rodent, the Nile grass rat (Arvicanthis niloticus), we first characterized the expression of the orexin receptors OX1R and OX2R in the DRN using in situ hybridization. The results revealed distinct distributions of OX1R and OX2R mRNAs, with OX1R predominantly expressed in the dorsal and lateral wings of the DRN that are involved in affective processes, while OX2R was mostly found in the ventral DRN that is more involved in sensory-motor function. We next examined how the orexin-OX1R pathway regulates 5-HT in the DRN and some of its projection sites using a selective OX1R antagonist SB-334867 (10 mg/kg, i.p.). A single injection of SB-334867 decreased 5-HT-ir fibers within the anterior cingulate cortex (aCgC); five once-daily administrations of SB-334867 decreased 5-HT-ir not only in the aCgC but also in the DRN, oval bed nucleus of the stria terminalis (ovBNST), nucleus accumbens shell (NAcSh), and periaqueductal gray (PAG). HPLC analysis revealed that five once-daily administrations of SB-334867 did not affect 5-HT turnover to any of the five sites, although it increased the levels of both 5-HT and 5-HIAA in the NAcSh. These results together suggest that orexinergic modulation of DRN 5-HT neurons via OX1Rs may be one pathway through which orexin regulates mood and anxiety, as well as perhaps other neurobiological processes.
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Affiliation(s)
- Widya Adidharma
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - Sean P Deats
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - Tomoko Ikeno
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - Jack W Lipton
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA; Department of Translational Science & Molecular Medicine, Michigan State University, Grand Rapids, MI, 49503, USA
| | - Joseph S Lonstein
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - Lily Yan
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
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17
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Pawluski JL, Li M, Lonstein JS. Serotonin and motherhood: From molecules to mood. Front Neuroendocrinol 2019; 53:100742. [PMID: 30878665 PMCID: PMC6541513 DOI: 10.1016/j.yfrne.2019.03.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/27/2019] [Accepted: 03/12/2019] [Indexed: 12/20/2022]
Abstract
Emerging research points to a valuable role of the monoamine neurotransmitter, serotonin, in the display of maternal behaviors and reproduction-associated plasticity in the maternal brain. Serotonin is also implicated in the pathophysiology of numerous affective disorders and likely plays an important role in the pathophysiology of maternal mental illness. Therefore, the main goals of this review are to detail: (1) how the serotonin system of the female brain changes across pregnancy and postpartum; (2) the role of the central serotonergic system in maternal caregiving and maternal aggression; and (3) how the serotonin system and selective serotonin reuptake inhibitor medications (SSRIs) are involved in the treatment of maternal mental illness. Although there is much work to be done, studying the central serotonin system's multifaceted role in the maternal brain is vital to our understanding of the processes governing matrescence and the maintenance of motherhood.
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Affiliation(s)
- Jodi L Pawluski
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail), UMR_S 1085, F-35000 Rennes, France.
| | - Ming Li
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE 68588-0308, USA.
| | - Joseph S Lonstein
- Neuroscience Program & Department of Psychology, Michigan State University, East Lansing, MI 48824, USA.
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