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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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2
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Chou S, Wu R, Li M. Long-term impacts of prenatal maternal immune activation and postnatal maternal separation on maternal behavior in adult female rats: Relevance to postpartum mental disorders. Behav Brain Res 2024; 461:114831. [PMID: 38142861 PMCID: PMC10872411 DOI: 10.1016/j.bbr.2023.114831] [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: 11/12/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
Early life adversities are known to exert long-term negative impacts on psychological and brain functions in adulthood. The present work examined how a prenatal brain insult and a postnatal stressor independently or interactively influence the quality of maternal care of postpartum female rats and their cognitive and emotional functions, as a way to identify the behavioral dysfunctions underlying childhood trauma-induced postpartum mental disorders (as indexed by impaired maternal care). Sprague-Dawley female offspring born from mother rats exposed to polyinosinic:polycytidylic acid (PolyI:C, 4.0-6.0 mg/kg) intended to cause gestational maternal immune activation (MIA) or saline were subjected to a repeated maternal separation stress (RMS, 3 h/day) or no separation for 9 days in the first two weeks of life (a 2 × 2 design). When these offspring became mothers, their attentional filtering ability (as measured in the prepulse inhibition of acoustic startle reflex test), positive hedonic response (as measured in the sucrose preference test), and negative emotional response (as measured in the startle reflex and fear-potentiated startle test) were examined, along with their home-cage maternal behavior. Virgin littermates served as controls in all the behavioral tests except in maternal behavior. Results showed that mother rats who experienced RMS displayed impaired nest building and crouching/nursing activities. RMS also interacted with MIA to alter pup retrieval latency and startle reactivity, such that MIA-RMS dams demonstrated significantly slower pup retrieval latency and higher startle magnitude compared to either RMS-only and MIA-only mothers. MIA also disrupted attentional filtering ability, with significantly lower prepulse inhibition. However, neither prenatal MIA nor postnatal RMS impaired sucrose preference or the acquisition of fear-potentiated startle. These results indicate that prenatal stress and postnatal adversity could impair maternal behavior individually, and interact with each other, causing impairments in attention, emotion and maternal motivation.
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Affiliation(s)
- Shinnyi Chou
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ruiyong Wu
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China
| | - Ming Li
- Department of Psychology, Nanjing University, Nanjing, China.
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3
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Seeman MV. Grappling with Issues of Motherhood for Women with Schizophrenia. Healthcare (Basel) 2023; 11:2882. [PMID: 37958026 PMCID: PMC10650198 DOI: 10.3390/healthcare11212882] [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: 10/06/2023] [Revised: 10/27/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
Despite the fact that most persons with schizophrenia find steady employment difficult to sustain, many women with this diagnosis embrace and fulfill the most difficult task of all-motherhood. The aim of this paper is to specify the challenges of motherhood in this population and review the treatment strategies needed to keep mothers and children safe, protecting health and fostering growth. The review addresses concerns that had been brought to the author's earlier attention during her clinical involvement with an outpatient clinic for women with psychosis. It is, thus, a non-systematic, narrative review of topic areas subjectively assessed as essential to "good enough" mothering in the context of schizophrenia. Questions explored are the stigma against motherhood in this population, mothers' painful choices, issues of contraception, abortion, child custody, foster care and kin placement of children, the effects of antipsychotics, specific perinatal delusional syndromes, and, finally, the availability of parental support. This review is intended for clinicians. Recommendations are that care providers work collaboratively with mothers, take note of their strengths as well as their failings, offer a wide array of family services, monitor households closely for safety and for treatment adherence, appreciating the many challenges women with schizophrenia face daily.
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Affiliation(s)
- Mary V Seeman
- Department of Psychiatry, University of Toronto, Toronto, ON M5S 1A1, Canada
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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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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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Cai Y, Zhang X, Jiang T, Zhong H, Han X, Ma R, Wu R. 8-OH-DPAT enhances dopamine D2-induced maternal disruption in rats. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:467-477. [DOI: 10.1007/s00359-022-01551-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 04/06/2022] [Accepted: 04/08/2022] [Indexed: 11/28/2022]
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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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Wu R, Huang Y, Liu Y, Shen Q, Han Y, Yang S, Wei W. Repeated predator odor exposure alters maternal behavior of postpartum Brandt's voles and offspring's locomotor activity. Behav Processes 2020; 177:104143. [PMID: 32445852 DOI: 10.1016/j.beproc.2020.104143] [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: 02/07/2020] [Revised: 05/03/2020] [Accepted: 05/17/2020] [Indexed: 12/21/2022]
Abstract
Recent evidence indicates that predation risk plays a special role in the rodent behavior of dams and offspring, but little is known about the effect of maternal exposure to the predator cues in the absence of pups. Here, we assessed the effects of repeated predator odor exposure on various maternal responses in postpartum Brandt's voles (Lasiopodomys brandtii). We also examined offspring's behavioral response to a novel environment. Only mother voles were exposed to distilled water, rabbit urine and cat urine for 60 min daily from postpartum day (PP) 1-18. Maternal behavior was immediately tested after these exposures on PP1, 3, 6, 9 and 18. Repeated cat odor (CO) and rabbit odor (RO) exposure disrupted hovering over pups in a time-dependent fashion. Repeated CO exposure also time-dependently disrupted pup retrieval, whereas RO exposure induced long-term reduction in pup licking. Juvenile offspring of CO-exposed mothers showed increased locomotor activity and decreased rearing in the open field at postnatal day 30. These findings demonstrated that maternal exposure to predator or non-predator odors had a disruptive effect on the maternal behavior of Brandt's voles when only the mother was exposed to these odors, and that the adversity experience with predation risk significantly impacted the behavioral development of offspring. Future work should explore possible behavioral mechanisms, such as the effect of predation risk, on the dams' emotional processing or pup preference.
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Affiliation(s)
- Ruiyong Wu
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yefeng Huang
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yuan Liu
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Qiuyi Shen
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yuxuan Han
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Shengmei Yang
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Wanhong Wei
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
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9
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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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10
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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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Gao J, Chen L, Li M. 5-HT 2A receptors modulate dopamine D 2-mediated maternal effects. Pharmacol Biochem Behav 2019; 180:32-43. [PMID: 30904543 DOI: 10.1016/j.pbb.2019.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 02/10/2019] [Accepted: 03/19/2019] [Indexed: 11/29/2022]
Abstract
Serotonin 5-HT2A receptors are expressed throughout the mesolimbic and mesocortical dopamine pathways, and manipulation of this receptor system has a profound impact on dopamine functions and dopamine-mediated behaviors. It is highly likely that 5-HT2A receptors may also modulate the D2-mediated maternal effects. The present study investigated this issue and also explored the possible behavioral mechanisms. We tested the effects of two D2 drugs (an agonist quinpirole: 0.5, 1.0 mg/kg, and a potent D2 antagonist haloperidol: 0.05, 0.10 mg/kg, sc) and their combinations with two 5-HT2A drugs (a selective 5-HT2A agonist TCB-2: 2.5 mg/kg, and 5-HT2A antagonist MDL100907, 1.0 mg/kg, sc) on maternal behavior in Sprague-Dawley postpartum females. Individually, TCB-2 (2.5 mg/kg, sc) and quinpirole (0.5 and 1.0 mg/kg, sc) reduced pup preference and disrupted home-cage maternal behavior. In contrast, haloperidol (0.10 mg/kg, sc) only disrupted home-cage maternal behavior, but did not suppress pup preference. MDL100907 (1.0 mg/kg, sc) by itself had no effect on either pup preference or maternal behavior. When administered in combination, pretreatment of TCB-2 did not alter quinpirole's disruption of pup preference and home-cage maternal behavior (possibly due to the floor effect), however, it did enhance haloperidol's disruption of pup retrieval in the home cage. MDL100907 had no effect both quinpirole's and haloperidol's disruption of pup preference and home-cage maternal behavior. Interestingly, haloperidol attenuated TCB-2's disruptive effect on pup preference. These findings suggest that activation of 5-HT2A receptors tends to enhance D2-mediated maternal disruption, whereas blockade of 5-HT2A receptors is less effective. They also suggest that 5-HT2A receptors may have a direct effect on maternal behavior independent of their interaction with D2 receptors. The possible behavioral and neural mechanisms by which 5-HT2A- and D2-mediated maternal effects and their interaction are discussed.
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Affiliation(s)
- Jun Gao
- Faculty of Psychology, Southwest University, Chongqing, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, China; Chongqing Collaborative Innovation Center for Brain Science, Chongqing, China.
| | - Leilei Chen
- Faculty of Psychology, Southwest University, Chongqing, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, China
| | - Ming Li
- Faculty of Psychology, Southwest University, Chongqing, China; Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE 68588-0308, USA; Chongqing Collaborative Innovation Center for Brain Science, Chongqing, China.
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Gan L, Sun M, Chen W. 5‑Hydroxytryptamine 2A receptor inverse agonist pimavanserin impairs maternal behavior in postpartum female rats. Pharmacol Biochem Behav 2018; 175:152-159. [DOI: 10.1016/j.pbb.2018.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/23/2018] [Accepted: 10/24/2018] [Indexed: 11/16/2022]
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Li X, Ding X, Wu R, Chen L, Gao J, Hu G, Li M. A behavioral mechanistic investigation of the role of 5-HT 1A receptors in the mediation of rat maternal behavior. Pharmacol Biochem Behav 2018; 169:16-26. [PMID: 29649502 DOI: 10.1016/j.pbb.2018.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/06/2018] [Accepted: 04/06/2018] [Indexed: 01/30/2023]
Abstract
Previous work suggests that 5-HT1A receptors play a special role in rodent maternal aggression, but not in other aspects of maternal care (e.g. pup retrieval and nest building). The present study re-assessed the basic effects of 5-HT1A activation or blockade on various maternal responses in postpartum female rats. We also examined the possible behavioral mechanisms underlying the maternal effects of 5-HT1A. Sprague-Dawley mother rats were injected with a 5-HT1A agonist 8-OH-DPAT (0.1, 0.5 or 1.0 mg/kg, sc), a 5-HT1A antagonist WAY-101405 (0.1, 0.5 or 1.0 mg/kg, sc) or 0.9% saline solution on postpartum days 3, 5, and 7. Maternal behavior was tested 30 min before, 30 min, 120 min, and 240 min after the injection. Acute and repeated 8-OH-DPAT treatment significantly disrupted pup retrieval, pup licking, nursing, and nest building in a dose-dependent fashion, whereas WAY-101405 had no effect at the tested doses. The 5-HT1A receptor specificity of 8-OH-DPAT's action was confirmed as its maternal disruption effect was reversed by pretreatment of WAY-100635 (a highly selective 5-HT1A receptor antagonist). Subsequent pup preference test found that 8-OH-DPAT did not decrease the pup preference over a novel object, thus no inhibition on maternal motivation or maternal affect. The pup separation test and pup retrieval on an elevated plus maze test also failed to find any motivational and motor impairment effect with 8-OH-DPAT. However, 8-OH-DPAT at the maternal disruptive dose did disrupt the prepulse inhibition (a measure of attentional function) of acoustic startle response and enhanced the basal startle response. These findings suggest that stimulation of 5-HT1A receptors by 8-OH-DPAT impairs maternal care by partially interfering with the attentional processing or basal anxiety. More work is needed to further delineate the psychological and neuronal mechanisms underlying the maternal disruptive effect of 5-HT1A receptor activation.
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Affiliation(s)
- Xiaonan Li
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, The First Peoples's Hospital of Changzhou, 185 Juqian Street, Changzhou, Jiangsu 213003, China; Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE 68588-0308, USA
| | - Xiaojing Ding
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing, Jiangsu 210023, China; Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE 68588-0308, USA
| | - Ruiyong Wu
- Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu 225009, China; Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE 68588-0308, USA
| | - Leilei Chen
- Faculty of Psychology, Southwest University, Chongqing, 400715, China
| | - Jun Gao
- Faculty of Psychology, Southwest University, Chongqing, 400715, China
| | - Gang Hu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing, Jiangsu 210023, China.
| | - Ming Li
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE 68588-0308, USA.
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Behavioral mechanisms underlying the maternal disruptive effect of serotonin 5-HT 2A receptor activation in Sprague-Dawley rats. J Neural Transm (Vienna) 2018; 125:1065-1075. [PMID: 29616335 DOI: 10.1007/s00702-018-1878-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
Abstract
Recent evidence indicates that acute activation of 5-HT2A receptors causes a disruption of maternal behavior in rats. However, the behavioral mechanisms underlying such a disruption are not known. We addressed this issue using two behavioral approaches targeting the maternal motivational and emotional processing systems. First, we used the pup-separation technique to increase maternal motivation to see whether pup separation is capable of reducing the maternal disruptive effect of TCB-2 (a high-affinity 5-HT2A agonist) treatment. On postpartum days 4 and 6, different groups of Sprague-Dawley dams were treated with the TCB-2 (5.0 mg/kg, sc) or vehicle and their maternal behaviors were tested after either a 4-h pup-separation or no-pup-separation condition. Although acute TCB-2 injection disrupted maternal behavior, this disruption was not attenuated by pup separation, even after we optimized the timing of separation to maximize its increase on maternal motivation. Acute TCB-2 also impaired the retrieval of food pellets, suggesting a general effect on motivated behaviors. Next, we used a pup preference test and found that dams treated with TCB-2 exhibited an even stronger preference to pups over a male conspecific than vehicle-treated dams, indicating an enhanced motivational and emotional processing of the rewarding property of pups. These findings suggest that TCB-2 has a disruptive effect on rat maternal behavior, and this disruption is not likely due to the drug's effect on mothers' motivational and emotional processing of the incentive salience of pups, although this motivational suppression account cannot be completely ruled out. Future work could explore other possible behavioral mechanisms, such as the drug's effect on executive function.
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16
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Activation of 5-HT 2A receptor disrupts rat maternal behavior. Neuropharmacology 2017; 128:96-105. [PMID: 28965828 DOI: 10.1016/j.neuropharm.2017.09.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/26/2017] [Accepted: 09/26/2017] [Indexed: 11/21/2022]
Abstract
Serotonin 5-HT2A receptor is widely distributed in the central nervous system and plays an important role in sensorimotor function, emotion regulation, motivation, executive control, learning and memory. We investigated its role in rat maternal behavior, a naturalistic behavior encompassing many psychological functions that the 5-HT2A receptor is involved in. We first showed that activation of 5-HT2A receptor by TCB-2 (a highly selective 5-HT2A agonist, 1, 2.5 or 5.0 mg/kg) disrupted maternal behavior dose-dependently, and this effect was reduced by pretreatment with a 5-HT2A receptor antagonist MDL 100907, but exacerbated by pretreatment with a 5-HT2C receptor antagonist SB242084 and a 5-HT2C receptor agonist MK212, indicating that the maternal disruptive effect of 5-HT2A activation is receptor-specific and can be modulated by 5-HT2C receptor bidirectionally. We then microinjected TCB-2 into two brain regions important for the normal expression of maternal behavior: the medial prefrontal cortex (mPFC) and the medial preoptic area (mPOA) and found that only acute intra-mPFC infusion of TCB-2 suppressed pup retrieval, whereas intra-mPOA had no effect. Finally, using c-Fos immunohistochemistry, we identified that the ventral bed nucleus of stria terminalis (vBNST), the central amygdala (CeA), and the dorsal raphe (DR) were additionally involved in the maternal-disruptive effect of TCB-2. These findings suggest that the 5-HT2A receptor in the mPFC and other maternally related regions is required for the normal expression of maternal behavior through its intrinsic action or interactions with other receptors (e.g. 5-HT2C). Functional disruption of this neuroreceptor system might contribute to postpartum mental disorders (e.g. depression and psychosis) that impair the quality of maternal care.
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