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Agrati D, Uriarte N. What can challenging reproductive contexts tell us about the rat's maternal behavior? Front Behav Neurosci 2023; 17:1239681. [PMID: 37521725 PMCID: PMC10375047 DOI: 10.3389/fnbeh.2023.1239681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 07/03/2023] [Indexed: 08/01/2023] Open
Abstract
Maternal behavior in mammals encompasses a complex repertoire of activities that ensure the survival of the offspring and shape their neural and behavioral development. The laboratory rat has been employed as a classic model for investigating maternal behavior, and recently with the use of advanced techniques, the knowledge of its neural basis has been expanded significantly. However, the standard laboratory testing conditions in which rats take care of a single litter impose constraints on the study of maternal flexibility. Interestingly, the reproductive characteristics of this species, including the existence of a fertile postpartum estrus, allow us to study maternal behavior in more complex and ethologically relevant contexts, even in laboratory settings. Here we review how maternal and sexual motivations interact during the postpartum estrus, shaping the behavioral response of females according to the presence of the pups and males. Next, we describe how impregnation during the postpartum estrus creates a new reproductive context in which mothers simultaneously care for two successive litters, adapting their responses to different behavioral and physiological demands of pups. These findings illustrate the behavioral adaptability of maternal rats to pups' needs and the presence of other reinforcers, as well as its dependence on the context. In our view, future perspectives in the field, by incorporating the use of cutting-edge techniques, should analyze maternal flexibility and its neural substrates in models that incorporate complex and challenging contexts. This approach would allow a more comprehensive understanding of brain circuits involved in the adaptive and flexible nature of parenting.
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Affiliation(s)
- Daniella Agrati
- Sección Fisiología y Nutrición, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Natalia Uriarte
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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2
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Zeppelini CG, Carvalho-Pereira T, Alves RS, Santiago DCC, Santo VFE, Begon M, Costa F, Khalil H. Demographic drivers of Norway rat populations from urban slums in Brazil. Urban Ecosyst 2021; 24:801-809. [PMID: 34720572 PMCID: PMC8550123 DOI: 10.1007/s11252-020-01075-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 11/27/2022]
Abstract
The Norway rat is a globally distributed pest, known for its resilience to eradication and control programs. Efficient population control, especially in urban settings, is dependent on knowledge of rat demography and population ecology. We analyzed the relationship between four demographic outcomes, estimated by live-trapping data, and fine-scale environmental features measured at the capture site. Wounds, a proxy for agonistic interactions, were associated with mature individuals. Areas with environmental features favorable to rats, such as open sewers and unpaved earth, were associated with more mature individuals with a better body condition index. The control measures (environmental stressors) are likely to be disrupting the social structure of rat colonies, increasing the frequency and distribution of agonistic interactions, which were common in both sexes and maturity states. The relationship between the favorable environmental conditions and the demographic markers analyzed indicate possible targets for infestation control through environmental manipulation, and could be incorporated into current pest management programs to achieve long-term success. Our study indicate that urban interventions focused on removal of potential resources for rats could be potential long-term solutions by reducing the carrying capacity of the environment. Supplementary Information The online version contains supplementary material available at 10.1007/s11252-020-01075-2.
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Affiliation(s)
- C G Zeppelini
- Laboratório de Mamíferos, Universidade Federal da Paraíba, Cidade Universitária, João Pessoa, Brazil.,Programa de Pós-Graduação em Ecologia: Teoria, Aplicações e Valores, Universidade Federal da Bahia, R. Barão do Geremoabo, Salvador, 147 Brazil
| | - T Carvalho-Pereira
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, R. Basílio da Gama, S/N, Salvador, Brazil
| | - R Sady Alves
- Programa de Pós-Graduação em Ciência Animal nos Trópicos, Universidade federal da Bahia, R. Barão do Geremoabo, Salvador, 147 Brazil
| | - D C C Santiago
- Instituto de Biologia, Universidade Federal da Bahia, R. Barão do Geremoabo, Salvador, 147 Brazil
| | - V F Espirito Santo
- Faculdade de Farmácia, Universidade Federal da Bahia, R. Barão do Geremoabo, Salvador, 147 Brazil
| | - M Begon
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, L69 7ZB UK
| | - F Costa
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, R. Basílio da Gama, S/N, Salvador, Brazil
| | - Hussein Khalil
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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3
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Shabalova AA, Liang M, Zhong J, Huang Z, Tsuji C, Shnayder NA, Lopatina O, Salmina AB, Okamoto H, Yamamoto Y, Zhong ZG, Yokoyama S, Higashida H. Oxytocin and CD38 in the paraventricular nucleus play a critical role in paternal aggression in mice. Horm Behav 2020; 120:104695. [PMID: 31987898 DOI: 10.1016/j.yhbeh.2020.104695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 01/21/2020] [Accepted: 01/21/2020] [Indexed: 10/25/2022]
Abstract
In mammals, the development of healthy offspring requires maternal care. Behavior by lactating mothers toward other individuals is an important component of maternal aggression. However, it is unclear whether fathers display aggression primed by pups (an external factor), and the protection mechanism is poorly understood. To address this question, we examined paternal aggression in the ICR mouse strain. We found that sires exposed to cues from pups and lactating dams showed stronger aggression toward intruders than did sires that were deprived of family cues or exposed to nonlactating mates. c-Fos immunohistochemistry showed that cells in both the paraventricular and supraoptic nuclei (PVN and SON, respectively) in the hypothalamus of sires exposed to any cues were highly activated. However, c-Fos activation in oxytocinergic neurons was increased only in sires exposed to pup cues and solely in the PVN. In Cd38-knockout sires, the presence of pups induced no or reduced parental aggression; however, this phenotype was recovered, that is, aggression increased to the wild-type level, after intraperitoneal administration of oxytocin (OT). Specific c-Fos activation patterns induced by pup cues were not found in the PVN of knockout sires. These results demonstrate that the PVN is one of the primary hypothalamic areas involved in paternal aggression and suggest that a CD38-dependent OT mechanism in oxytocinergic neurons is critical for part of the behavior associated with the protection of offspring by nurturing male mice.
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Affiliation(s)
- Anna A Shabalova
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Department of Socioneurosciences, United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Kanazawa Campus, Kanazawa 920-8640, Japan
| | - Mingkun Liang
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, Guangxi 530011, China
| | - Jing Zhong
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Department of Physiology, Guangxi University of Chinese Medicine, Xianhu Campus, Nanning, Guangxi 530200, China
| | - Zhiqi Huang
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Pharmaceutical Sciences, Guangxi University of Chinese Medicine, Xianhu Campus, Nanning, Guangxi 530200, China
| | - Chiharu Tsuji
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Natalia A Shnayder
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Olga Lopatina
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Laboratory for Social Brain Studies, Research Institute of Molecular Medicine and Pathobiochemistry, Department of Biochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasentsky, Krasnoyarsk 660022, Russia
| | - Alla B Salmina
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Laboratory for Social Brain Studies, Research Institute of Molecular Medicine and Pathobiochemistry, Department of Biochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasentsky, Krasnoyarsk 660022, Russia
| | - Hiroshi Okamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8640, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8640, Japan
| | - Zeng-Guo Zhong
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Center of Research & Development of New Drugs, Guangxi Traditional Chinese Medical University, Guangxi Zhuang Autonomous Region, Nanning 530001, China
| | - Shigeru Yokoyama
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Haruhiro Higashida
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan; Laboratory for Social Brain Studies, Research Institute of Molecular Medicine and Pathobiochemistry, Department of Biochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasentsky, Krasnoyarsk 660022, Russia.
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Grieb ZA, Holschbach MA, Lonstein JS. Interaction between postpartum stage and litter age on maternal caregiving and medial preoptic area orexin. Physiol Behav 2018; 194:430-436. [PMID: 29928888 PMCID: PMC6089372 DOI: 10.1016/j.physbeh.2018.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/11/2018] [Accepted: 06/17/2018] [Indexed: 01/15/2023]
Abstract
Most maternal caregiving behaviors change across lactation to match the developmental needs of the continuously aging offspring. However, it is mostly unknown whether the dams' postpartum stage or litter age is the primary driving force of these changes. In this study, postnatal day 1 and 8 litters were cross-fostered or in-fostered to postpartum day 1 or 8 dams. Five days later, undisturbed observations of maternal caregiving behaviors were performed on the subsequent two days. We found a main effect of dams' postpartum stage on the frequency that mothers spent with the pups and displayed erect postures over them (hovering over and kyphosis), although it was mostly driven by an interaction between postpartum stage and litter age: early-postpartum dams were in contact with younger litters and in erect postures more often with younger litters compared to later-postpartum dams with younger litters. Additionally, there was an interaction between postpartum stage and litter age on the litter weights because older litters living with later-postpartum dams were heavier than older litters living with early-postpartum dams. There was also an interaction between postpartum stage and litter age on the dams' bodyweight, with early-postpartum dams living with younger litters weighing the least and later-postpartum dams living with younger litters weighing the most. Because activity of the neuropeptide, orexin, within the medial preoptic area (mPOA) has been implicated in maternal nursing and other caregiving behaviors, we measured mPOA levels of orexin-A but it was not affected by postpartum stage or litter age (nor was there an interaction). However, high orexin-A was negatively associated with the frequency of contact with pups and the display of erect postures. These results indicate that changes in caregiving across lactation are driven by endogenous factors in the dams, age-related cues they receive from offspring, and interactions between these factors.
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Affiliation(s)
- Z A Grieb
- Neuroscience Program, 108 Giltner Hall, Michigan State University, East Lansing, MI 48824, United States.
| | - M A Holschbach
- Neuroscience Program, 108 Giltner Hall, Michigan State University, East Lansing, MI 48824, United States
| | - J S Lonstein
- Neuroscience Program, 108 Giltner Hall, Michigan State University, East Lansing, MI 48824, United States
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5
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Rickenbacher E, Perry RE, Sullivan RM, Moita MA. Freezing suppression by oxytocin in central amygdala allows alternate defensive behaviours and mother-pup interactions. eLife 2017; 6. [PMID: 28606306 PMCID: PMC5469614 DOI: 10.7554/elife.24080] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/09/2017] [Indexed: 01/05/2023] Open
Abstract
When animals and their offspring are threatened, parents switch from self-defense to offspring protection. How self-defense is suppressed remains elusive. We postulated that suppression of the self-defense response, freezing, is gated via oxytocin acting in the centro-lateral amygdala (CeL). We found that rat dams conditioned to fear an odor, froze when tested alone, whereas if pups were present, they remained in close contact with them or targeted the threat. Furthermore, blocking oxytocin signaling in the CeL prevented the suppression of maternal freezing. Finally, pups exposed to the odor in the presence of the conditioned dam later froze when re-exposed alone. However, if oxytocin signaling in the dam had been blocked, pups failed to learn. This study provides a functional role for the well-described action of oxytocin in the central amygdala, and demonstrates that self-defense suppression allows for active pup protection and mother-pup interactions crucial for pup threat learning. DOI:http://dx.doi.org/10.7554/eLife.24080.001 Animals have many mechanisms to avoid or defend themselves against deadly encounters with predators. However, adult animals frequently put themselves at risk while protecting their more vulnerable offspring from attacks. For example, a killdeerbird with young will fake a broken wing and lead a predator away from its nest. This helps ensure that the parent’s genes live on and contribute to the survival of their species. To do this, the parent must override his or her own defense mechanisms and protect the young instead of themselves. Little is known about the exact mechanisms that allow animals to suppress their own defense mechanisms while protecting their young. Freezing is one tactic that animals will use when they are unable to escape a predator. Previously, studies have shown that the hormone oxytocin, which is produced in the brain, suppresses freezing behavior. Oxytocin plays an important role in birth and breastfeeding, but it is also known to strengthen the bond between individuals, in particular between mother and child. Until now, it was not known whether this hormone also blocks self-defense behaviors in animals protecting their offspring. Now, Rickenbacher et al. show that oxytocin does indeed block freezing behavior, enabling mother rats to protect their offspring in the face of a threatening smell. In the experiments, mother rats were taught to fear the scent of peppermint. Without their young, these rats would freeze whenever they smelled peppermint. Yet, when mother rats with their pups were exposed to the scent, they did not freeze. Instead, they tried to defend their young. Blocking oxytocin in a part of the mothers’ brains called the amygdala, however, caused them to freeze in response to the scent of peppermint, even in the presence of their pups. The experiments show that oxytocin helps mother rats suppress their self-defense mechanisms and is necessary for the mothers to protect their young. Rickenbacher et al. also showed that pups of oxytocin-treated mothers did not learn to freeze in response to the threat. But pups of untreated mothers who defended them, learned to freeze when they were exposed to the scent of peppermint. A next step will be to record neurons that produce oxytocin to better understand how the presence of the pups stimulate its production in their mothers. In addition, it is still unclear how pups learn from their mothers to freeze in response to a threat. One possibility is that the mother produces a molecule that signals danger. Identifying this molecule would be the next step. DOI:http://dx.doi.org/10.7554/eLife.24080.002
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Affiliation(s)
| | - Rosemarie E Perry
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, United States.,Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, United States.,Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, New York, United States.,New York University Child Study Center, New York University School of Medicine, New York, United States.,Department of Child and Adolescent Psychiatry, New York University School of Medicine, New York, United States
| | - Regina M Sullivan
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, New York, United States.,New York University Child Study Center, New York University School of Medicine, New York, United States.,Department of Child and Adolescent Psychiatry, New York University School of Medicine, New York, United States
| | - Marta A Moita
- Champalimaud Neuroscience Programme, LIsboa, Portugal
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Pereira M, Ferreira A. Neuroanatomical and neurochemical basis of parenting: Dynamic coordination of motivational, affective and cognitive processes. Horm Behav 2016; 77:72-85. [PMID: 26296592 DOI: 10.1016/j.yhbeh.2015.08.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/13/2015] [Accepted: 08/13/2015] [Indexed: 02/06/2023]
Abstract
This article is part of a Special Issue "Parental Care". Becoming a parent is arguably the most profound transforming experience in life. It is also inherently very emotionally and physically demanding, such that the reciprocal interaction with the young changes the brain and behavior of the parents. In this review, we examine the neurobiological mechanisms of parenting primarily discussing recent research findings in rodents and primates, especially humans. We argue that it is essential to consider parenting within a conceptual framework that recognizes the dynamics of the reciprocal mother-young relationship, including both the complexity and neuroplasticity of its underlying mechanisms. Converging research suggests that the concerted activity of a distributed network of subcortical and cortical brain structures regulates different key aspects of parenting, including the sensory analysis of infant stimuli as well as motivational, affective and cognitive processes. The interplay among these processes depends on the action of various neurotransmitters and hormones that modulate the timely and coordinated execution of caregiving responses of the maternal circuitry exquisitely attuned to the young's affect, needs and developmental stage. We conclude with a summary and a set of questions that may guide future research.
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Affiliation(s)
- Mariana Pereira
- Department of Psychological and Brain Sciences, University of Massachusetts, Amherst, USA.
| | - Annabel Ferreira
- Sección Fisiología y Nutrición, Facultad de Ciencias, Universidad de la República, Uruguay
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de Almeida RMM, Ferreira A, Agrati D. Sensory, hormonal, and neural basis of maternal aggression in rodents. Curr Top Behav Neurosci 2014; 17:111-130. [PMID: 24841427 DOI: 10.1007/7854_2014_312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We review existing knowledge of the neural, hormonal, and sensory basis of maternal aggression in the female rat. Although females may express different kinds of aggression, such as defense or dominance, the most frequent and conspicuous form of aggressive behavior among females is the one associated with motherhood. Maternal aggression occurs in various vertebrate and invertebrate species; however, our emphasis will be on maternal aggression in rats because most of the physiological investigations have been performed in this species. Firstly, we address those factors that predispose the female to attack, such as the endocrine profile, the maternal state, and the stimulation provided by the pups, as well as those that trigger the aggressive response, as the intruder's characteristics and the context. As the postpartum aggression is a fundamental component of the maternal repertoire, we emphasize its association with maternal motivation and the reduction of fear and anxiety in dams. Finally, we outline the neurocircuitry involved in the control of maternal aggression, stressing the role of the ventro-orbital region of prefrontal cortex and the serotoninergic system.
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Affiliation(s)
- Rosa Maria Martins de Almeida
- Laboratório de Psicologia Experimental, Neurociências e Comportamento (LPNeC), Instituto de Psicologia do Desenvolvimento e da Personalidade da Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil,
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8
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Perez-Torrero E, Salas M. Early undernourishment interferes with the maternal aggressive response triggered by an intruder entering the homing cage. Nutr Neurosci 2013; 10:17-22. [PMID: 17539479 DOI: 10.1080/10284150601165110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The maternal aggressive response (MAR) against intruders is temporarily expressed during lactation in association with the rearing and protection of offspring to promote their survival and growth in the nest. This normal component of maternal behaviour requires both the hormonal changes occurring at the end of pregnancy and the presence of pups for its establishment. Because early food restriction in the rat results in long-term maternal deficiencies, we analysed in Wistar rats the effects of perinatal undernutrition on the MAR to an intruder at days 1, 4, and 8 postpartum. The data showed that undernourished dams exhibited significant reductions of sniffing frequency on days 4 and 8 and significant increases of biting on day 4 and of lateral attacks on postpartum days 4 and 8. The finding of an altered MAR during the lactating period may be relevant for the survival and long-term behavioural development of the progeny.
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Affiliation(s)
- Esther Perez-Torrero
- Department of Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, Universidad Nacional Autónoma de México, Campus UNAM Juriquilla, Querétaro 76001, Mexico.
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9
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Bosch OJ. Maternal aggression in rodents: brain oxytocin and vasopressin mediate pup defence. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130085. [PMID: 24167315 DOI: 10.1098/rstb.2013.0085] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The most significant social behaviour of the lactating mother is maternal behaviour, which comprises maternal care and maternal aggression (MA). The latter is a protective behaviour of the mother serving to defend the offspring against a potentially dangerous intruder. The extent to which the mother shows aggressive behaviour depends on extrinsic and intrinsic factors, as we have learned from studies in laboratory rodents. Among the extrinsic factors are the pups' presence and age, as well as the intruders' sex and age. With respect to intrinsic factors, the mothers' innate anxiety and the prosocial brain neuropeptides oxytocin (OXT) and arginine vasopressin (AVP) play important roles. While OXT is well known as a maternal neuropeptide, AVP has only recently been described in this context. The increased activities of these neuropeptides in lactation are the result of remarkable brain adaptations peripartum and are a prerequisite for the mother to become maternal. Consequently, OXT and AVP are significantly involved in mediating the fine-tuned regulation of MA depending on the brain regions. Importantly, both neuropeptides are also modulators of anxiety, which determines the extent of MA. This review provides a detailed overview of the role of OXT and AVP in MA and the link to anxiety.
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Affiliation(s)
- Oliver J Bosch
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, , Regensburg 93040, Germany
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10
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Konoshenko MY, Plyusnina IZ. Behavioral effects of bidirectional selection for behavior towards human in virgin and lactate Norway rats. Behav Processes 2012; 90:180-8. [PMID: 22301096 DOI: 10.1016/j.beproc.2012.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 12/07/2011] [Accepted: 01/16/2012] [Indexed: 10/14/2022]
Abstract
Although numerous studies have demonstrated strong differences in behavioral, hormonal and neurobiological characteristics between male rats selected for elimination (tame) and enhancement (aggressive) of aggressiveness towards humans, few studies have examined changes in female behavior under this selection. The objective of the current work was to evaluate the effects of bidirectional selection for aggressiveness towards humans on behavioral profiles of virgin and lactating rats compared with the behavior in tame, aggressive and unselected (wild-type) females. The behavior of virgin females was studied using the light-dark box, the startle response test and the modified glove test. Tame females were less anxious and more tolerant towards humans than unselected and aggressive rats. Principal component analysis of all behavioral parameters produced three independent factors, explaining 66.37% of the total variability. The measures of behavior towards humans and the measures of anxiety mainly loaded on PC1 (first principal component) which separated the tame females from the unselected and aggressive ones. These data suggest the genetic correlation between the selected behavior towards humans and anxiety-related behavior in virgin rats. No significant effect of line was found for PC2 scores, associated with risk assessment behavior. Measurements of freezing behavior mainly loaded on PC3, and this component separated rats of different genetic groups from each other. The behavior of lactating rats was studied in maternal defense and pup retrieval tests. Females of selected lines did not significantly differ in behavioral measurements of these tests and were characterized by higher maternal motivation than unselected rats. It is suggested that long-term breeding of tame and aggressive rats in captivity has reduced the threshold for maternal behavior.
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Affiliation(s)
- Maria Yu Konoshenko
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, pr. Lavrentjeva 10, Novosibirsk, Russia
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Andino N, Reus L, Cappa FM, Campos VE, Giannoni SM. Social Environment and Agonistic Interactions: Strategies in a Small Social Mammal. Ethology 2011. [DOI: 10.1111/j.1439-0310.2011.01956.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Pereira M, Morrell JI. The changing role of the medial preoptic area in the regulation of maternal behavior across the postpartum period: facilitation followed by inhibition. Behav Brain Res 2009; 205:238-48. [PMID: 19549547 PMCID: PMC2769204 DOI: 10.1016/j.bbr.2009.06.026] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 06/10/2009] [Accepted: 06/14/2009] [Indexed: 01/21/2023]
Abstract
Maternal behavior in rats undergoes considerable plasticity in parallel to the developmental stage of the pups, resulting in distinct patterns of maternal behavior and care at different postpartum time points. The medial preoptic area (mPOA) of the hypothalamus is one critical neural substrate underlying the onset and early expression of maternal behavior in rats but little is known about its specific functional role in the evolving expression of maternal behavior across the postpartum period. The present study uses a reversible local neural inactivation method to examine the role of the mPOA in the regulation of maternal behavior throughout the postpartum period, particularly extending into the late postpartum, a little examined period. This approach avoids the compensatory plasticity in CNS that occurs after permanent lesions, and allows the repeated testing of same individuals. Early (PPD7-8) and late (PPD13-14) postpartum maternal behavior was evaluated in female rats following infusions of bupivacaine or vehicle into the mPOA or into control areas. As expected, mPOA inactivation severely but transiently disrupted early postpartum maternal behavior whereas infusion of vehicle or inactivation of adjacent control sites did not. Later in the postpartum period, however, transient mPOA inactivation facilitated the expression of maternal behaviors, highly contrasting the behavioral expression levels characteristic of late postpartum. Results strongly demonstrate that the mPOA is differentially engaged throughout postpartum in orchestrating appropriate maternal responses with the developmental stage of the pups.
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Affiliation(s)
- Mariana Pereira
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark Campus, NJ 07102, USA.
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13
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Abstract
Recent studies in both animals and humans indicate that gonadal hormones have profound control over emotional states, and certainly contribute to the increased occurrence of psychiatric illness in women. Reports, as reviewed here, suggest that two important regions of the limbic system, the central nucleus of the amygdala (CeA) and the bed nucleus of the stria terminalis (BNST), control different aspects of emotional behaviour. Short-term cue-specific emotional responses, like Pavlovian fear conditioning, require activation of the CeA, while long-duration and contextual emotional responses, are dependant on the BNST. There is accumulating experimental evidence that gender and sex hormones specifically modulate BNST-mediated anxiety behaviours. Moreover, the functional separation between the CeA and the BNST may be exaggerated during lactation in the rat, a time of profound hormonal and behavioural change. In this study, the effects of sex hormones on fear and anxiety are reviewed with an emphasis on the differential effects of these hormones on functions subserved by the BNST as opposed to the CeA. Studies, as highlighted here, looking at sex hormone and gender effects on the ability of corticotrophin-releasing factor and bright ambient light to enhance startle, emphasise the importance of understanding both the effect of, and brain region where, gonadal hormones exert their control over emotional behaviour.
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Affiliation(s)
- D Toufexis
- Emory University, Department of Psychiatry, Yerkes National Primate Centre, Atlanta, GA 30329, USA.
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14
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Bosch OJ, Müsch W, Bredewold R, Slattery DA, Neumann ID. Prenatal stress increases HPA axis activity and impairs maternal care in lactating female offspring: implications for postpartum mood disorder. Psychoneuroendocrinology 2007; 32:267-78. [PMID: 17337328 DOI: 10.1016/j.psyneuen.2006.12.012] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 12/15/2006] [Accepted: 12/18/2006] [Indexed: 10/23/2022]
Abstract
Early life stress is believed to constitute a risk factor for the development of mood disorders later in life. In the present study, we hypothesized that prenatal stress (PS) exerts long-lasting effects in female rat offspring, resulting in impaired adaptations to stress during lactation and, as such, may be a contributory factor to postpartum mood disorders. PS increased anxiety in adult virgin females compared with controls. During lactation, PS dams nursed significantly less and spent less time with pups compared with controls, whereas dams did not differ in pup retrieval or maternal aggression. HPA axis reactivity was elevated in response to a mild stressor in PS dams compared to their controls, but not in virgins, with the delta corticosterone response returning to the higher level seen in virgins. Moreover, corticotropin-releasing hormone (CRH) mRNA expression within the parvocellular region of the paraventricular nucleus (PVN) was increased in both virgins and dams exposed to PS compared with the relative controls, while the attenuation in expression in lactating controls was abolished following PS. In addition, arginine vasopressin (AVP) mRNA was increased in the parvocellular, but not magnocellular part of the PVN, in both PS-exposed virgins and lactating dams compared with their relative controls; although expression was also higher in controls during lactation compared with virgins. Thus, the present study demonstrates that exposure to PS results in long-lasting behavioural and neuroendocrine alterations in the female offspring, which are manifested during the lactation period. Furthermore, it implicates PS as a potential risk factor for the development of postpartum mood disorders, and that alterations in the HPA axis reactivity, at least partially, are involved.
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Affiliation(s)
- Oliver J Bosch
- Department of Zoology, Institute of Zoology, University of Regensburg, 93040 Regensburg, Germany
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15
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Bosch OJ, Krömer SA, Neumann ID. Prenatal stress: opposite effects on anxiety and hypothalamic expression of vasopressin and corticotropin-releasing hormone in rats selectively bred for high and low anxiety. Eur J Neurosci 2006; 23:541-51. [PMID: 16420461 DOI: 10.1111/j.1460-9568.2005.04576.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We studied the mechanisms of genetic-early environmental interactions to modulate adult stress-coping and tested the hypothesis that prenatal stress (PS) can differentially alter the consequences of a genetic predisposition to either hyper- or hypo-anxiety. Exposure of male Wistar rats, bred for high (HAB) or low (LAB) anxiety-related behaviour, to PS between pregnancy days 4 and 18 resulted in opposite effects on anxiety in adulthood, i.e. HAB rats became less and LAB rats became more anxious compared with their unstressed controls (plus-maze and holeboard). The high anxiety of HAB controls was accompanied by elevated expression of vasopressin and corticotropin-releasing hormone (CRH) mRNA within the hypothalamic paraventricular nucleus compared with LAB rats. PS reduced CRH mRNA expression in HAB rats but increased vasopressin mRNA expression in LAB rats, which may explain the opposite effects of PS on adult emotionality. Differential effects of PS were also found with respect to hypothalamo-pituitary-adrenal axis reactivity; the hypothalamo-pituitary-adrenal hyper-response in virgin female HAB controls became attenuated after PS, without affecting plasma corticosterone concentrations in LAB rats. Differences in maternal plasma corticosterone measured between pregnancy days 6 and 14 of HAB and LAB dams or differential effects of PS on maternal behaviour can be excluded. In conclusion, exposure of rats with genetically determined high or low emotionality to PS mitigates the extremes in behavioural and neuroendocrine stress-coping, thus allowing adequate and similar behavioural responses to potentially dangerous stimuli in adulthood. Differential effects of PS on the activity of the brain vasopressin and CRH systems might represent possible underlying molecular mechanisms.
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Affiliation(s)
- Oliver J Bosch
- Department of Zoology, University of Regensburg, 93040 Regensburg, Germany
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16
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Tu MT, Lupien SJ, Walker CD. Measuring stress responses in postpartum mothers: perspectives from studies in human and animal populations. Stress 2005; 8:19-34. [PMID: 16019595 DOI: 10.1080/10253890500103806] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Reduced hypothalamic-pituitary-adrenal (HPA) responses to stress during the last week of pregnancy and lactation have been consistently observed in rat studies. Several contributing factors have been proposed for this phenomenon in lactation, including the suckling stimulus from the pups, hormones (oxytocin and prolactin) and opioids, a decrease in the ability of noradrenaline to potentiate hypothalamic responses and changes in pituitary responsiveness to ACTH secretagogues (AVP and CRF). In contrast to this vast literature using the rat model, only few studies have addressed this issue in the human population. The consensus is that women engaging in breastfeeding activities exhibit reduced anxiety, although the reductions in neuroendocrine and autonomic responses to stressors are variable, in part because of the different nature of the stressors used. Further work is required to investigate how additional factors, such as maternal parity or emotional salience of the stressor can affect stress responsiveness in postpartum women. Here, we review first the findings regarding stress responsiveness during lactation in both rat and human studies, and then discuss potential research avenues and methodological issues that could be the lead to future research protocols in human subjects. Knowing the reciprocal relationship in the mother-infant dyad, it is clear that investigation of the mechanisms regulating stress responses and mental health in postpartum mothers can only be beneficial to the development of the infant.
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Affiliation(s)
- Mai Thanh Tu
- Department of Psychiatry, Douglas Hospital Research Center, McGill University, Montreal, Canada
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17
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Lonstein JS. Reduced anxiety in postpartum rats requires recent physical interactions with pups, but is independent of suckling and peripheral sources of hormones. Horm Behav 2005; 47:241-55. [PMID: 15708752 DOI: 10.1016/j.yhbeh.2004.11.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/02/2004] [Accepted: 11/03/2004] [Indexed: 11/19/2022]
Abstract
Changes in emotional behavior occur across the reproductive cycle in female rodents, with reduced anxiety found during the postpartum period, but relatively little is known about factors contributing to this decreased anxiety. Using increased duration of time spent in the open arms of an elevated plus-maze as an indicator of reduced anxiety, it was found in a series of experiments that (1) anxiety is significantly reduced in Long-Evans females during the first week of lactation, but not thereafter, (2) relatively recent contact with pups before testing (within 4 h) is necessary for their reduced anxiety, (3) dams that receive only distal sensory cues from pups for the 4 h prior to testing do not show reduced anxiety, (4) the absence of nipples, and therefore a lack of suckling by pups, has no effect on dams' anxiety, (5) cesarean delivery of pups 2 days prior to expected parturition did not alter later anxiety in dams, (6) hypophysectomy during mid-pregnancy or ovariectomy within 24 h after parturition also did not prevent reduced anxiety in dams, and (7) differences in anxiety between lactating and virgin females are greatest 4-8 min after being placed in the plus-maze. Therefore, exposure to their own peripheral hormones through mid-pregnancy is sufficient to prime female rats to show reduced anxiety, but only if they later have recent physical interaction with pups. Furthermore, because suckling and the peripheral hormones released during suckling appear to be unnecessary, decreased anxiety in maternal rats may instead be regulated by the transient intracerebral release of neuropeptides or neurotransmitters while dams receive other types of tactile inputs from their infants.
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Affiliation(s)
- Joseph S Lonstein
- Program in Neuroscience, Department of Psychology, Giltner Hall, Michigan State University, East Lansing, MI 48823, USA.
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18
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Lonstein JS, Gammie SC. Sensory, hormonal, and neural control of maternal aggression in laboratory rodents. Neurosci Biobehav Rev 2002; 26:869-88. [PMID: 12667494 DOI: 10.1016/s0149-7634(02)00087-8] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Parental animals of many rodent species display fierce and persistent aggression toward unfamiliar conspecifics that appears to protect their often altricial and defenseless young. We herein review studies of the sensory, hormonal, neuroanatomical, and neurochemical mechanisms underlying maternal aggression in laboratory rodents. The relationship between maternal aggression and fearfulness or anxiety is also discussed.
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Affiliation(s)
- Joseph S Lonstein
- Program in Neuroscience and Department of Psychology, Michigan State University, East Lansing 48824, USA.
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