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Gutierrez-Castellanos N, Dias IC, Husain BFA, Lima S. Functional diversity along the anteroposterior axis of the ventromedial hypothalamus. J Neuroendocrinol 2024:e13447. [PMID: 39253818 DOI: 10.1111/jne.13447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 08/14/2024] [Accepted: 08/28/2024] [Indexed: 09/11/2024]
Abstract
Innate behaviors ensure animal survival and reproductive success. Defending their territory, escaping from predators or mating with a sexual partner, are fundamental behaviors determining the ecological fitness of individuals. Remarkably, all these behaviors share a common neural substrate, as they are under the control of the ventromedial hypothalamus (VMH). Decades of research have contributed to understanding the exquisite diversity of functional ensembles underlying the wide array of functions that the VMH carries out. These functional ensembles are usually distributed throughout the dorsoventral and mediolateral axes of this nucleus. However, increasing evidence is bringing to attention the functional diversity of the VMH across its anteroposterior axis. In this review, we will overview our current understanding of how different ensembles within the VMH control a wide array of animal behaviors, emphasizing the newly discovered roles for its anterior subdivision in the context of conspecific self-defense.
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Affiliation(s)
| | - Inês C Dias
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | | | - Susana Lima
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
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2
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López-González L, Martínez-de-la-Torre M, Puelles L. Populational heterogeneity and partial migratory origin of the ventromedial hypothalamic nucleus: genoarchitectonic analysis in the mouse. Brain Struct Funct 2023; 228:537-576. [PMID: 36598560 PMCID: PMC9944059 DOI: 10.1007/s00429-022-02601-y] [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: 08/22/2022] [Accepted: 11/27/2022] [Indexed: 01/05/2023]
Abstract
The ventromedial hypothalamic nucleus (VMH) is one of the most distinctive hypothalamic tuberal structures, subject of numerous classic and modern functional studies. Commonly, the adult VMH has been divided in several portions, attending to differences in cell aggregation, cell type, connectivity, and function. Consensus VMH partitions in the literature comprise the dorsomedial (VMHdm), and ventrolateral (VMHvl) subnuclei, which are separated by an intermediate or central (VMHc) population (topographic names based on the columnar axis). However, some recent transcriptome analyses have identified a higher number of different cell types in the VMH, suggesting additional subdivisions, as well as the possibility of separate origins. We offer a topologic and genoarchitectonic developmental study of the mouse VMH complex using the prosomeric axis as a reference. We analyzed genes labeling specific VMH subpopulations, with particular focus upon the Nkx2.2 transcription factor, a marker of the alar-basal boundary territory of the prosencephalon, from where some cells seem to migrate dorsoventrally into VMH. We also identified separate neuroepithelial origins of a Nr2f1-positive subpopulation, and a new Six3-positive component, as well as subtle differences in origin of Nr5a1 positive versus Nkx2.2-positive cell populations entering dorsoventrally the VMH. Several of these migrating cell types are born in the dorsal tuberal domain and translocate ventralwards to reach the intermediate tuberal domain, where the adult VMH mass is located in the adult. This work provides a more detailed area map on the intrinsic organization of the postmigratory VMH complex, helpful for deeper functional studies of this basal hypothalamic entity.
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Affiliation(s)
- Lara López-González
- grid.10586.3a0000 0001 2287 8496University of Murcia, IMIB-Arrixaca Institute of Biomedical Research, El Palmar, 30120 Murcia, Spain
| | - Margaret Martínez-de-la-Torre
- grid.10586.3a0000 0001 2287 8496University of Murcia, IMIB-Arrixaca Institute of Biomedical Research, El Palmar, 30120 Murcia, Spain
| | - Luis Puelles
- University of Murcia, IMIB-Arrixaca Institute of Biomedical Research, El Palmar, 30120, Murcia, Spain.
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3
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Benevento M, Hökfelt T, Harkany T. Ontogenetic rules for the molecular diversification of hypothalamic neurons. Nat Rev Neurosci 2022; 23:611-627. [PMID: 35906427 DOI: 10.1038/s41583-022-00615-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2022] [Indexed: 11/09/2022]
Abstract
The hypothalamus is an evolutionarily conserved endocrine interface that, among other roles, links central homeostatic control to adaptive bodily responses by releasing hormones and neuropeptides from its many neuronal subtypes. In its preoptic, anterior, tuberal and mammillary subdivisions, a kaleidoscope of magnocellular and parvocellular neuroendocrine command neurons, local-circuit neurons, and neurons that project to extrahypothalamic areas are intermingled in partially overlapping patches of nuclei. Molecular fingerprinting has produced data of unprecedented mass and depth to distinguish and even to predict the synaptic and endocrine competences, connectivity and stimulus selectivity of many neuronal modalities. These new insights support eminent studies from the past century but challenge others on the molecular rules that shape the developmental segregation of hypothalamic neuronal subtypes and their use of morphogenic cues for terminal differentiation. Here, we integrate single-cell RNA sequencing studies with those of mouse genetics and endocrinology to describe key stages of hypothalamus development, including local neurogenesis, the direct terminal differentiation of glutamatergic neurons, transition cascades for GABAergic and GABAergic cell-derived dopamine cells, waves of local neuronal migration, and sequential enrichment in neuropeptides and hormones. We particularly emphasize how transcription factors determine neuronal identity and, consequently, circuit architecture, and whether their deviations triggered by environmental factors and hormones provoke neuroendocrine illnesses.
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Affiliation(s)
- Marco Benevento
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Tomas Hökfelt
- Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, Solna, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria. .,Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, Solna, Sweden.
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Zhou X, Zhong S, Peng H, Liu J, Ding W, Sun L, Ma Q, Liu Z, Chen R, Wu Q, Wang X. Cellular and molecular properties of neural progenitors in the developing mammalian hypothalamus. Nat Commun 2020; 11:4063. [PMID: 32792525 PMCID: PMC7426815 DOI: 10.1038/s41467-020-17890-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
The neuroendocrine hypothalamus is the central regulator of vital physiological homeostasis and behavior. However, the cellular and molecular properties of hypothalamic neural progenitors remain unexplored. Here, hypothalamic radial glial (hRG) and hypothalamic mantle zone radial glial (hmRG) cells are found to be neural progenitors in the developing mammalian hypothalamus. The hmRG cells originate from hRG cells and produce neurons. During the early development of hypothalamus, neurogenesis occurs in radial columns and is initiated from hRG cells. The radial glial fibers are oriented toward the locations of hypothalamic subregions which act as a scaffold for neuronal migration. Furthermore, we use single-cell RNA sequencing to reveal progenitor subtypes in human developing hypothalamus and characterize specific progenitor genes, such as TTYH1, HMGA2, and FAM107A. We also demonstrate that HMGA2 is involved in E2F1 pathway, regulating the proliferation of progenitor cells by targeting on the downstream MYBL2. Different neuronal subtypes start to differentiate and express specific genes of hypothalamic nucleus at gestational week 10. Finally, we reveal the developmental conservation of nuclear structures and marker genes in mouse and human hypothalamus. Our identification of cellular and molecular properties of neural progenitors provides a basic understanding of neurogenesis and regional formation of the non-laminated hypothalamus.
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Affiliation(s)
- Xin Zhou
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Suijuan Zhong
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China
| | - Honghai Peng
- Department of Neurosurgery, Jinan Central Hospital Affiliated to Shandong University, Shandong, 250013, China
| | - Jing Liu
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenyu Ding
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China
| | - Le Sun
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qiang Ma
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zeyuan Liu
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruiguo Chen
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qian Wu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China
| | - Xiaoqun Wang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Brain-Intelligence Technology (Shanghai), Bioland Laboratory (Guangzhou), Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.
- Advanced Innovation Center for Human Brain Protection, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
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Schwerdtfeger LA, Tobet SA. From organotypic culture to body-on-a-chip: A neuroendocrine perspective. J Neuroendocrinol 2019; 31:e12650. [PMID: 30307079 DOI: 10.1111/jne.12650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 12/22/2022]
Abstract
The methods used to study neuroendocrinology have been as diverse as the discoveries to come out of the field. Maintaining live neurones outside of a body in vitro was important from the beginning, building on methods that dated back to at least the first decade of the 20th Century. Neurosecretion defines an essential foundation of neuroendocrinology based on work that began in the 1920s and 1930s. Throughout the first half of the 20th Century, many paradigms arose for studying everything from single neurones to whole organs in vitro. Two of these survived as preeminent systems for use throughout the second half of the century: cell cultures and explant systems. Slice cultures and explants that emerged as organotypic technologies included such neuroendocrine organs such as the brain, pituitary, adrenals and intestine. The vast majority of these studies were carried out in static cultures for which media were changed over a time scale of days. Tissues were used for experimental techniques such as electrical recording of neuronal physiology in single cells and observation by live microscopy. When maintained in vitro, many of these systems only partially capture the in vivo physiology of the organ system of interest, often because of a lack of cellular diversity (eg, neuronal cultures lacking glia). Modern microfluidic methodologies show promise for organ systems, ranging from the reproductive to the gastrointestinal to the brain. Moving forward and striving to understand the mechanisms that drive neuroendocrine signalling centrally and peripherally, there will always be a need to consider the heterogeneous cellular compositions of organs in vivo.
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Affiliation(s)
- Luke A Schwerdtfeger
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Stuart A Tobet
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado
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6
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Kobayashi M, Shimizu-Okabe C, Kim J, Kobayashi S, Matsushita M, Masuzaki H, Takayama C. Embryonic development of GABAergic terminals in the mouse hypothalamic nuclei involved in feeding behavior. Neurosci Res 2018; 134:39-48. [PMID: 29174921 DOI: 10.1016/j.neures.2017.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 10/18/2017] [Accepted: 11/20/2017] [Indexed: 11/29/2022]
Abstract
The inhibitory neurotransmitter gamma-amino butyric acid (GABA) plays important roles in energy balance and feeding behavior in the hypothalamus. To reveal the time course of GABAergic network formation, we examined the immunohistochemical localization of glutamic acid decarboxylase (GAD), a GABAergic neuron marker, vesicular GABA transporter (VGAT), a marker of inhibitory terminals, and K+-Cl--cotransporter2 (KCC2), which shifts GABA action from excitation to inhibition, in the developing mouse hypothalamus. GABAergic terminals, seen as GAD- and VGAT-positive dots, increased in density during embryonic development. Moreover, the onset of KCC2 localization was almost concomitant with GABAergic terminal formation, and KCC2-positive profiles increased in density during development. This suggested that after the formation of GABAergic terminals, GABAergic action may change to inhibition in the hypothalamus. This maturation appears to proceed as follows: the lateral hypothalamus (LH) matures first, followed by the paraventricular nucleus (PVN) by the time of birth, while the ventromedial hypothalamus (VMH) and the arcuate nucleus (Arc) are not fully mature at the time of birth. Our findings suggest that GABAergic networks in the "feeding center" (LH) and the "exit" (PVN) may mature before birth, while those in the "satiety center" (VMH) and "higher control center" (Arc) may mature after birth.
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Affiliation(s)
- Masato Kobayashi
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Chigusa Shimizu-Okabe
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Jeongtae Kim
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Shiori Kobayashi
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Masayuki Matsushita
- Department of Molecular and Cellular Physiology, School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Hiroaki Masuzaki
- Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Chitoshi Takayama
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan.
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7
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Feng H, Wang Q, Guo F, Han X, Pang M, Sun X, Gong Y, Xu L. Nesfatin-1 influences the excitability of gastric distension-responsive neurons in the ventromedial hypothalamic nucleus of rats. Physiol Res 2016; 66:335-344. [PMID: 27982684 DOI: 10.33549/physiolres.933347] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The present study investigated the effects of nesfatin-1 on gastric distension (GD)-responsive neurons via an interaction with corticotropin-releasing factor (CRF) receptor signaling in the ventromedial hypothalamic nucleus (VMH), and the potential regulation of these effects by hippocampal projections to VMH. Extracellular single-unit discharges were recorded in VHM following administration of nesfatin-1. The projection of nerve fibers and expression of nesfatin-1 were assessed by retrograde tracing and fluoro-immunohistochemical staining, respectively. Results showed that there were GD-responsive neurons in VMH; Nesfatin-1 administration and electrical stimulation of hippocampal CA1 sub-region altered the firing rate of these neurons. These changes could be partially blocked by pretreatment with the non-selective CRF antagonist astressin-B or an antibody to NUCB2/nesfatin-1. Electrolytic lesion of CA1 hippocampus reduced the effects of nesfatin-1 on VMH GD-responsive neuronal activity. These studies suggest that nesfatin-1 plays an important role in GD-responsive neuronal activity through interactions with CRF signaling pathways in VMH. The hippocampus may participate in the modulation of nesfatin-1-mediated effects in VMH.
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Affiliation(s)
- Hongzhen Feng
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong, PR China.
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8
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Frahm KA, Tobet SA. Development of the blood-brain barrier within the paraventricular nucleus of the hypothalamus: influence of fetal glucocorticoid excess. Brain Struct Funct 2014; 220:2225-34. [PMID: 24817635 PMCID: PMC4481307 DOI: 10.1007/s00429-014-0787-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 04/23/2014] [Indexed: 01/08/2023]
Abstract
The blood–brain barrier (BBB) is a critical contributor to brain function. To understand its development and potential function in different brain regions, the postnatal (P) BBB was investigated in the mouse cortex (CTX), lateral hypothalamus, and paraventricular nucleus of the hypothalamus (PVN). Brains were examined on postnatal days (P)12, P22 and P52 for BBB competency and for pericytes as key cellular components of the BBB demarcated by immunoreactive desmin. Glucocorticoid influences (excess dexamethasone; dex) during prenatal development were also assessed for their impact on the blood vessels within these regions postnatally. At P12, there was significantly more extravascular leakage of a low molecular weight dye (fluorescein isothiocyanate) in the CTX than within hypothalamic regions. For pericytes, there were low levels of desmin immunoreactivity at P12 that increased with age for all regions. There was more desmin immunoreactivity present in the PVN at each age examined. Fetal dex exposure resulted in decreased blood vessel density within the PVN at P20. In the CTX, dex exposure increased BBB competency, in contrast to the PVN where there was a decrease in BBB competency and increased pericyte presence. Overall, unique alterations in the functioning of the BBB within the PVN may provide a novel mechanism for fetal antecedent programming that may influence adult disorders.
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Affiliation(s)
- Krystle A Frahm
- Program in Cell and Molecular Biology, Colorado State University, 1617 Campus Delivery, Fort Collins, CO, 80523-1617, USA
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9
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Frahm KA, Nash CP, Tobet SA. Endocan immunoreactivity in the mouse brain: method for identifying nonfunctional blood vessels. J Immunol Methods 2013; 398-399:27-32. [PMID: 24055127 DOI: 10.1016/j.jim.2013.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/01/2013] [Accepted: 09/09/2013] [Indexed: 02/02/2023]
Abstract
Endocan is a secreted proteoglycan that has been shown to indicate angiogenic activity: remodeling in several tumor types in humans and mice. Serum endocan levels also indicate prognosis and has been proposed as a biomarker for certain cancers. Recently, monoclonal antibodies directed against mouse endocan have been developed allowing for further characterization of endocan function and potentially as a marker for angiogenesis through immunoreactivity in endothelial tip cells. The results of the current study show that endocan immunoreactivity in the mouse brain is present in blood vascular networks including but not limited to the cortex, hippocampus and paraventricular nucleus of the hypothalamus in C57BL/6J and FVB/N mice. Endocan immunoreactivity did not vary during postnatal development or by sex. Interestingly, after vascular perfusion with fluorescein isothiocyanate (FITC), endothelial cells positive for FITC were immunonegative for endocan suggesting FITC interference with the immunohistochemistry. A small number of FITC-negative blood vessels were endocan immunoreactive suggesting the identification of new blood vessels that are not yet functional. The current study shows that endocan is normally present in the mouse brain and prior vascular perfusion with FITC may provide a useful tool for identify newly forming blood vessels.
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Affiliation(s)
- Krystle A Frahm
- Program in Cell & Molecular Biology, Colorado State University, Department of Biomedical Sciences, Fort Collins, CO, USA; Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
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10
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Tobet SA, Walker HJ, Seney ML, Yu KW. Viewing cell movements in the developing neuroendocrine brain. Integr Comp Biol 2012; 43:794-801. [PMID: 21680478 DOI: 10.1093/icb/43.6.794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many studies suggest that migratory guidance cues within the developing brain are diverse across many regions. To better understand the early development and differentiation of select brain regions, an in vitro method was developed using selected inbred and transgenic strains of embryonic mice. In particular, organotypic slices are used to test factors that influence the movements of neurons during brain development. Thick 250 μm slices cut on a vibrating microtome are prepared and maintained in vitro for 0-3 days. Nissl stain analyses often show a uniform distribution of cells in the regions of interest on the day of plating (embryonic days 12-15). After 3 days in vitro, cellular aggregation suggesting nuclear formation or the changing position of cells with a defined phenotype show that reasonably normal cell movements occur in several regions. Movements in vitro that mimic changes in vivo suggest that key factors reside locally within the plane of the slices. Video microscopy studies are used to follow the migration of fluorescently labeled cells in brain slices from mice maintained in serum-free media for 1 to 3 days. Transgenic mice with selective promoter driven expression of fluorescent proteins allow us to view specific cell types (e.g., neurons expressing gonadotropin-releasing hormone). The accessibility of an in vitro system that provides for relatively normal brain development over key brief windows of time allows for the testing of important mechanisms.
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Affiliation(s)
- Stuart A Tobet
- Colorado State University, Department of Biomedical Sciences, Fort Collins, Colorado 80523
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11
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Nugent BM, Tobet SA, Lara HE, Lucion AB, Wilson ME, Recabarren SE, Paredes AH. Hormonal programming across the lifespan. Horm Metab Res 2012; 44:577-86. [PMID: 22700441 PMCID: PMC3756611 DOI: 10.1055/s-0032-1312593] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Hormones influence countless biological processes across an animal's lifespan. Many hormone-mediated events occur within developmental sensitive periods, during which hormones have the potential to cause permanent tissue-specific alterations in anatomy and physiology. There are numerous selective critical periods in development with different targets being affected during different periods. This review outlines the proceedings of the Hormonal Programming in Development session at the US-South American Workshop in Neuroendocrinology in August 2011. Here we discuss how gonadal steroid hormones impact various biological processes within the brain and gonads during early development and describe the changes that take place in the aging female ovary. At the cellular level, hormonal targets in the brain include neurons, glia, or vasculature. On a genomic/epigenomic level, transcription factor signaling and epigenetic changes alter the expression of critical hormone receptor genes across development and following ischemic brain insult. In addition, organizational hormone exposure alters epigenetic processes in specific brain nuclei and may be an important mediator of sexual differentiation of the neonatal brain. Brain targets of hormonal programming, such as the paraventricular nucleus of the hypothalamus, may be critical in influencing the development of peripheral targets, such as the ovary. Exposure to excess hormones can cause abnormalities in the ovary during development leading to polycystic ovarian syndrome (PCOS). Exposure to excess androgens during fetal development also has a profound effect on the development of the male reproductive system. In addition, increased activity of the sympathetic nerve and stress during early life have been linked to PCOS symptomology in adulthood. Finally, we describe how age-related decreases in fertility are linked to high levels of nerve growth factor (NGF), which enhances sympathetic nerve activity and alters ovarian function.
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Affiliation(s)
- B M Nugent
- University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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All-<I>trans</I> Retinoic Acid Promotes Cell Apoptosis Through Gamma Amino Butyric Acid Pathway in Murine Embryonic Palate Mesenchymal Cells. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2011.00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Abstract
Steroidogenic factor 1 (SF-1; officially designated NR5a1) is a member of a nuclear receptor superfamily with important roles in the development of endocrine systems. Studies with global and tissue-specific (i.e. central nervous system) knockout mice have revealed several roles of SF-1 in brain. These include morphological effects on the development of the ventromedial nucleus of the hypothalamus and functional effects on body weight regulation through modulation of physical activity, anxiety-like behaviours and female sexual behaviours. Although such defects are almost certainly a result of the absence of SF-1 acting as a transcription factor in the hypothalamus, global SF-1 knockout mice also represent a model for studying the sex differences in the brain that develop in the absence of exposure to foetal sex steroid hormones as a result of the absence of gonads. In the present review, current knowledge of the roles of SF-1 protein in the central nervous system is discussed.
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Affiliation(s)
- T Büdefeld
- Centre for Animal Genomics, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
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14
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Büdefeld T, Tobet SA, Majdic G. Altered position of cell bodies and fibers in the ventromedial region in SF-1 knockout mice. Exp Neurol 2011; 232:176-84. [PMID: 21906594 DOI: 10.1016/j.expneurol.2011.08.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 07/14/2011] [Accepted: 08/22/2011] [Indexed: 11/16/2022]
Abstract
The ventromedial nucleus of the hypothalamus (VMH) is a key cell group in the medial-basal hypothalamus that participates in the regulation of energy balance. Previous studies have shown that the cellular organization of the VMH is altered in mice with a disruption of the steroidogenic factor-1 (NR5a1) gene (SF-1 KO mice). The present study examined orexigenic/anorexigenic peptides (neuropeptide Y (NPY), agouti-related peptide (AgRP) and cocaine- and amphetamine-regulated transcript (CART)) and neural connections to and from the VMH in SF1 KO mice. NeuroVue tracing and Golgi staining were used to evaluate connections between the preoptic area (POA) and VMH and the orientation of dendrites in the VMH, respectively. Results of this study reveal changes in the cytoarchitecture of the region of the VMH with respect to the distribution of immunoreactive NPY, AgRP and CART. In WT mice projections from the POA normally surround the VMH while in SF-1 KO mice, projections from the POA stream through the region that would otherwise be VMH. Golgi impregnation of the region revealed fewer dendrites with ventrolateral orientations and in general, more variable dendritic orientations in SF-1 KO mice providing additional evidence that the connectivity of cells in the region is likely altered due to the cellular rearrangements consequent to disruption of the NR5a1 gene. In conclusion, this study greatly extends the data showing that the morphology of the regions containing the VMH is disrupted in SF-1 KO mice and suggests that changes in the location of cells or fibers containing NPY, AgRP and CART may, in part, account for changes in body weight homeostasis in these mice.
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Affiliation(s)
- Tomaz Büdefeld
- Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Slovenia
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Aujla PK, Bora A, Monahan P, Sweedler JV, Raetzman LT. The Notch effector gene Hes1 regulates migration of hypothalamic neurons, neuropeptide content and axon targeting to the pituitary. Dev Biol 2011; 353:61-71. [PMID: 21354131 DOI: 10.1016/j.ydbio.2011.02.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 02/14/2011] [Accepted: 02/16/2011] [Indexed: 10/18/2022]
Abstract
Proper development of the hypothalamic-pituitary axis requires precise neuronal signaling to establish a network that regulates homeostasis. The developing hypothalamus and pituitary utilize similar signaling pathways for differentiation in embryonic development. The Notch signaling effector gene Hes1 is present in the developing hypothalamus and pituitary and is required for proper formation of the pituitary, which contains axons of arginine vasopressin (AVP) neurons from the hypothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON). We hypothesized that Hes1 is necessary for the generation, placement and projection of AVP neurons. We found that Hes1 null mice show no significant difference in cell proliferation or death in the developing diencephalon at embryonic day 10.5 (e10.5) or e11.5. By e16.5, AVP cell bodies are formed in the SON and PVN, but are abnormally placed, suggesting that Hes1 may be necessary for the migration of AVP neurons. GAD67 immunoreactivity is ectopically expressed in Hes1 null mice, which may contribute to cell body misplacement. Additionally, at e18.5 Hes1 null mice show continued misplacement of AVP cell bodies in the PVN and SON and additionally exhibit abnormal axonal projection. Using mass spectrometry to characterize peptide content, we found that Hes1 null pituitaries have aberrant somatostatin (SS) peptide, which correlates with abnormal SS cells in the pituitary and misplaced SS axon tracts at e18.5. Our results indicate that Notch signaling facilitates the migration and guidance of hypothalamic neurons, as well as neuropeptide content.
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Affiliation(s)
- Paven K Aujla
- University of Illinois at Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, IL 61801, USA
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16
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McClellan KM, Stratton MS, Tobet SA. Roles for gamma-aminobutyric acid in the development of the paraventricular nucleus of the hypothalamus. J Comp Neurol 2010; 518:2710-28. [PMID: 20506472 PMCID: PMC2879086 DOI: 10.1002/cne.22360] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The development of the hypothalamic paraventricular nucleus (PVN) involves several factors that work together to establish a cell group that regulates neuroendocrine functions and behaviors. Several molecular markers were noted within the developing PVN, including estrogen receptors (ER), neuronal nitric oxide synthase (nNOS), and brain-derived neurotrophic factor (BDNF). By contrast, immunoreactive gamma-aminobutyric acid (GABA) was found in cells and fibers surrounding the PVN. Two animal models were used to test the hypothesis that GABA works through GABA(A) and GABA(B) receptors to influence the development of the PVN. Treatment with bicuculline to decrease GABA(A) receptor signaling from embryonic day (E) 10 to E17 resulted in fewer cells containing immunoreactive (ir) ERalpha in the region of the PVN vs. control. GABA(B)R1 receptor subunit knockout mice were used to examine the PVN at P0 without GABA(B) signaling. In female but not male GABA(B)R1 subunit knockout mice, the positions of cells containing ir ERalpha shifted from medial to lateral compared with wild-type controls, whereas the total number of ir ERalpha-containing cells was unchanged. In E17 knockout mice, ir nNOS cells and fibers were spread over a greater area. There was also a significant decrease in ir BDNF in the knockout mice in a region-dependent manner. Changes in cell position and protein expression subsequent to disruption of GABA signaling may be due, in part, to changes in nNOS and BDNF signaling. Based on the current study, the PVN can be added as another site where GABA exerts morphogenetic actions in development.
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Affiliation(s)
- Kristy M. McClellan
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
- School of Science, Buena Vista University, Storm Lake, IA 50588
| | - Matthew S. Stratton
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Stuart A. Tobet
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
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Gagnidze K, Pfaff DW, Mong JA. Gene expression in neuroendocrine cells during the critical period for sexual differentiation of the brain. SEX DIFFERENCES IN THE HUMAN BRAIN, THEIR UNDERPINNINGS AND IMPLICATIONS 2010; 186:97-111. [DOI: 10.1016/b978-0-444-53630-3.00007-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Tobet S, Knoll JG, Hartshorn C, Aurand E, Stratton M, Kumar P, Searcy B, McClellan K. Brain sex differences and hormone influences: a moving experience? J Neuroendocrinol 2009; 21:387-92. [PMID: 19207813 PMCID: PMC2669491 DOI: 10.1111/j.1365-2826.2009.01834.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sex differences in the nervous system come in many forms. Although a majority of sexually dimorphic characteristics in the brain have been described in older animals, mechanisms that determine sexually differentiated brain characteristics often operate during critical perinatal periods. Both genetic and hormonal factors likely contribute to physiological mechanisms in development to generate the ontogeny of sexual dimorphisms in brain. Relevant mechanisms may include neurogenesis, cell migration, cell differentiation, cell death, axon guidance and synaptogenesis. On a molecular level, there are several ways to categorize factors that drive brain development. These range from the actions of transcription factors in cell nuclei that regulate the expression of genes that control cell development and differentiation, to effector molecules that directly contribute to signalling from one cell to another. In addition, several peptides or proteins in these and other categories might be referred to as 'biomarkers' of sexual differentiation with undetermined functions in development or adulthood. Although a majority of sex differences are revealed as a direct consequence of hormone actions, some may only be revealed after genetic or environmental disruption. Sex differences in cell positions in the developing hypothalamus, and steroid hormone influences on cell movements in vitro, suggest that cell migration may be one target for early molecular actions that impact brain development and sexual differentiation.
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Affiliation(s)
- S Tobet
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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McClellan KM, Calver AR, Tobet SA. GABAB receptors role in cell migration and positioning within the ventromedial nucleus of the hypothalamus. Neuroscience 2007; 151:1119-31. [PMID: 18248902 DOI: 10.1016/j.neuroscience.2007.11.048] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 11/20/2007] [Accepted: 11/28/2007] [Indexed: 12/16/2022]
Abstract
The ventromedial (VMN) and arcuate (ARC) nuclei of the hypothalamus are bilateral nuclear groups at the base of the hypothalamus that are organized through the aggregation of neurons born along the third ventricle that migrate laterally. During development, GABAergic neurons and fibers surround the forming (or primordial) VMN while neurons containing GABA receptors are found within the boundaries of the emerging nucleus. To investigate the role that GABAB receptors play in establishing the VMN, Thy-1 yellow fluorescent protein (YFP) mice were utilized for live video microscopy studies. The Thy-1 promoter drives YFP expression in regions of the hypothalamus during development. Administration of the GABAB receptor antagonist saclofen and the GABAA receptor antagonist bicuculline selectively increased the rate of VMN cell movement in slices placed in vitro at embryonic day 14, when cells that form both the ARC and VMN are migrating away from the proliferative zone surrounding the third ventricle. To further test the role of GABAB receptors in VMN development, GABAB receptor knockout mice were used to examine changes in the positions of phenotypically identified cells within the VMN. Cells containing immunoreactive estrogen receptors (ER) alpha were located in the ventrolateral quadrant of the wild type VMN. In GABABR1 knockout mice, these ERalpha positive neurons were located in more dorsal positions at postnatal day (P) 0 and P4. We conclude that GABA alters cell migration and its effect on final cell positioning may lead to changes in the circuitry and connections within specific nuclei of the developing hypothalamus.
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Affiliation(s)
- K M McClellan
- Department of Biomedical Sciences, Colorado State University, 1617 Campus Delivery, Fort Collins, CO 80523, USA
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20
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Edelmann M, Wolfe C, Scordalakes EM, Rissman EF, Tobet S. Neuronal nitric oxide synthase and calbindin delineate sex differences in the developing hypothalamus and preoptic area. Dev Neurobiol 2007; 67:1371-81. [PMID: 17638388 PMCID: PMC3622702 DOI: 10.1002/dneu.20507] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Throughout the hypothalamus there are several regions known to contain sex differences in specific cellular, neurochemical, or cell grouping characteristics. The current study examined the potential origin of sex differences in calbindin expression in the preoptic area and hypothalamus as related to sources of nitric oxide. Specific cell populations were defined by immunoreactive (ir) calbindin and neuronal nitric oxide synthase (nNOS) in the preoptic area/anterior hypothalamus (POA/AH), anteroventral periventricular nucleus (AVPv), and ventromedial nucleus of the hypothalamus (VMN). The POA/AH of adult mice was characterized by a striking sex difference in the distribution of cells with ir-calbindin. Examination of the POA/AH of androgen receptor deficient Tfm mice suggests that this pattern was in part androgen receptor dependent, since Tfm males had reduced ir-calbindin compared with wild-type males and more similar to wild-type females. At P0 ir-calbindin was more prevalent than in adulthood, with males having significantly more ir-calbindin and nNOS than have females. Cells that contained either ir-calbindin or ir-nNOS in the POA/AH were in adjacent cell groups, suggesting that NO derived from the enzymatic activity of nNOS may influence the development of ir-calbindin cells. In the region of AVPv, at P0, there was a sex difference with males having more ir-nNOS fibers than have females while ir-calbindin was not detected. In the VMN, at P0, ir-nNOS was greater in females than in males, with no significant difference in ir-calbindin. We suggest that NO as an effector molecule and calbindin as a molecular biomarker illuminate key aspects of sexual differentiation in the developing mouse brain.
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Ferguson C, Hardy SL, Werner DF, Hileman SM, Delorey TM, Homanics GE. New insight into the role of the beta3 subunit of the GABAA-R in development, behavior, body weight regulation, and anesthesia revealed by conditional gene knockout. BMC Neurosci 2007; 8:85. [PMID: 17927825 PMCID: PMC2100059 DOI: 10.1186/1471-2202-8-85] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 10/10/2007] [Indexed: 11/27/2022] Open
Abstract
Background The β3 subunit of the γ-aminobutyric acid type A receptor (GABAA-R) has been reported to be important for palate formation, anesthetic action, and normal nervous system function. This subunit has also been implicated in the pathogenesis of Angelman syndrome and autism spectrum disorder. To further investigate involvement of this subunit, we previously produced mice with a global knockout of β3. However, developmental abnormalities, compensation, reduced viability, and numerous behavioral abnormalities limited the usefulness of that murine model. To overcome many of these limitations, a mouse line with a conditionally inactivated β3 gene was engineered. Results Gene targeting and embryonic stem cell technologies were used to create mice in which exon 3 of the β3 subunit was flanked by loxP sites (i.e., floxed). Crossing the floxed β3 mice to a cre general deleter mouse line reproduced the phenotype of the previously described global knockout. Pan-neuronal knockout of β3 was achieved by crossing floxed β3 mice to Synapsin I-cre transgenic mice. Palate development was normal in pan-neuronal β3 knockouts but ~61% died as neonates. Survivors were overtly normal, fertile, and were less sensitive to etomidate. Forebrain selective knockout of β3 was achieved using α CamKII-cre transgenic mice. Palate development was normal in forebrain selective β3 knockout mice. These knockouts survived the neonatal period, but ~30% died between 15–25 days of age. Survivors had reduced reproductive fitness, reduced sensitivity to etomidate, were hyperactive, and some became obese. Conclusion Conditional inactivation of the β3 gene revealed novel insight into the function of this GABAA-R subunit. The floxed β3 knockout mice described here will be very useful for conditional knockout studies to further investigate the role of the β3 subunit in development, ethanol and anesthetic action, normal physiology, and pathophysiologic processes.
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Affiliation(s)
- Carolyn Ferguson
- Departments of Anesthesiology and Pharmacology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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22
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Cancedda L, Fiumelli H, Chen K, Poo MM. Excitatory GABA action is essential for morphological maturation of cortical neurons in vivo. J Neurosci 2007; 27:5224-35. [PMID: 17494709 PMCID: PMC6672363 DOI: 10.1523/jneurosci.5169-06.2007] [Citation(s) in RCA: 287] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 03/07/2007] [Accepted: 03/26/2007] [Indexed: 11/21/2022] Open
Abstract
GABA exerts excitatory actions on embryonic and neonatal cortical neurons, but the in vivo function of this GABA excitation is essentially unknown. Using in utero electroporation, we eliminated the excitatory action of GABA in a subpopulation of rat ventricular progenitors and cortical neurons derived from these progenitors by premature expression of the Cl- transporter KCC2, as confirmed by the changes in the reversal potential of GABA-induced currents and the resting membrane potential after GABA(A) receptor blockade. We found that radial migration to layer II/III of the somatosensory cortex of neurons derived from the transfected progenitors was not significantly affected, but their morphological maturation was markedly impaired. Furthermore, reducing neuronal excitability of cortical neurons in vivo by overexpressing an inward-rectifying K+ channel, which lowered the resting membrane potential, mimicked the effect of premature KCC2 expression. Thus, membrane depolarization caused by early GABA excitation is critical for morphological maturation of neonatal cortical neurons in vivo.
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Affiliation(s)
- Laura Cancedda
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California 94720-3200
| | - Hubert Fiumelli
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California 94720-3200
| | - Karen Chen
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California 94720-3200
| | - Mu-ming Poo
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California 94720-3200
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Abstract
Neurons that synthesize GnRH are critical brain regulators of the reproductive axis, yet they originate outside the brain and must migrate over long distances and varied environments to get to their appropriate positions during development. Many studies, past and present, are providing clues for the types of molecules encountered and movements expected along the migratory route. Recent studies provide real-time views of the behavior of GnRH neurons in the context of in vitro preparations that model those in vivo. Live images provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more alterations in direction after they enter the brain. The heterogeneity of molecular phenotypes for GnRH neurons likely ensures that multiple external factors will be found that regulate the migration of different portions of the GnRH neuronal population at different steps along the route. Molecules distributed in gradients both in the peripheral olfactory system and basal forebrain may be particularly influential in directing the appropriate movement of GnRH neurons along their arduous migration. Molecules that mediate the adhesion of GnRH neurons to changing surfaces may also play critical roles. It is likely that the multiple external factors converge on selective signal transduction pathways to engage the mechanical mechanisms needed to modulate GnRH neuronal movement and ultimately migration.
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Affiliation(s)
- Stuart A Tobet
- Colorado State University, Department of Biomedical Sciences, 1617 Campus Delivery, Fort Collins, Colorado 80523, USA
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24
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King BM. The rise, fall, and resurrection of the ventromedial hypothalamus in the regulation of feeding behavior and body weight. Physiol Behav 2006; 87:221-44. [PMID: 16412483 DOI: 10.1016/j.physbeh.2005.10.007] [Citation(s) in RCA: 335] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
Early researchers found that lesions of the ventromedial hypothalamus (VMH) resulted in hyperphagia and obesity in a variety of species including humans, which led them to designate the VMH as the brain's "satiety center." Many researchers later dismissed a role for the VMH in feeding behavior when Gold claimed that lesions restricted to the VMH did not result in overeating and that obesity was observed only with lesions or knife cuts that extended beyond the borders of the VMH and damaged or severed the ventral noradrenergic bundle (VNAB) or paraventricular nucleus (PVN). However, anatomical studies done both before and after Gold's study did not replicate his results with lesions, and in nearly every published direct comparison of VMH lesions vs. PVN or VNAB lesions, the group with VMH lesions ate substantially more food and gained twice as much weight. Several other important differences have also been found between VMH and both PVN and VNAB lesion-induced obesity. Concerns regarding (a) motivation to work for food and (b) the effects of nonirritative lesions have also been addressed and answered in many studies. Lesion studies with weanling rats and adult pair-tube-fed rats, as well as recent studies of knockout mice deficient in the orphan nuclear receptor steroidogenic factor 1, indicate that VMH lesion-induced obesity is in large part a metabolic obesity (due to autonomic nervous system disorders) independent of hyperphagia. However, there is ample evidence that the VMH also plays a primary role in feeding behavior. Neuroimaging studies in humans have shown a marked increase in activity in the area of the VMH during feeding. The VMH has a large population of glucoresponsive neurons that dynamically respond to blood glucose levels and numerous histamine, dopamine, serotonin, and GABA neurons that respond to feeding-related stimuli. Recent studies have implicated melanocortins in the VMH regulation of feeding behavior: food intake decreases when arcuate nucleus pro-opiomelanocortin (POMC) neurons activate VMH brain-derived neurotrophic factor (BDNF) neurons. Moderate hyperphagia and obesity have also been observed in female rats with damage to the efferent projections from the posterodorsal amygdala to the VMH. Hypothalamic obesity can result from damage to either the POMC or BDNF neurons. The concept of hypothalamic feeding and satiety centers is outdated and unnecessary, and progress in understanding hypothalamic mechanisms of feeding behavior will be achieved only by appreciating the different types of neural and blood-borne information received by the various nuclei, and then attempting to determine how this information is integrated to obtain a balance between energy intake and energy output.
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Affiliation(s)
- Bruce M King
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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25
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Handforth A, Delorey TM, Homanics GE, Olsen RW. Pharmacologic evidence for abnormal thalamocortical functioning in GABA receptor beta3 subunit-deficient mice, a model of Angelman syndrome. Epilepsia 2006; 46:1860-70. [PMID: 16393151 DOI: 10.1111/j.1528-1167.2005.00287.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE gamma-Aminobutyric acid receptor (GABA(A)r) subunit beta3-deficient mice model Angelman syndrome by displaying impaired learning, abnormal EEG with interictal spikes and slowing, myoclonus, and convulsions. The beta3-subunit deficiency causes a failure of intrathalamic reticular nucleus inhibition, leading to abnormally synchronized thalamocortical oscillations. We postulated that this pathophysiology underlies the abnormal cortical EEG and triggers interictal spikes and seizures, but extrathalamic regions also contribute to interictal spikes and seizures, so that the EEG slowing should reveal an absence-like response profile, whereas spikes and seizures have dual responsiveness to absence and partial-seizure drugs. METHODS Recording electrodes were implanted over the parietal cortices of wild-type, heterozygotes, and homozygous null mice. In each experiment, EEG was recorded for 45 min, either drug or vehicle administered, and EEG recorded for another 3 h. Each EEG was scored for slow-wave activity, interictal spikes, and seizures by a reader blinded to treatments. RESULTS Interictal spiking and percentage of time in EEG slowing in heterozygotes were increased by the proabsence drug baclofen (GABA(B)-receptor agonist), whereas CGP 35348 (GABA(B)-receptor antagonist) had the opposite effect. The antiabsence drug ethosuximide markedly suppressed EEG slowing and interictal spiking in heterozygote and null mice. Broad-spectrum clonazepam and valproate were more effective on interictal spiking than on EEG slowing, and fosphenytoin suppressed only interictal spiking. CONCLUSIONS The results suggest that this model of Angelman syndrome, although not expressing typical absence seizures, is characterized by hypersynchronous thalamocortical oscillations that possess absence-like pharmacologic responsiveness and promote EEG slowing, interictal spikes, and convulsive seizures.
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Affiliation(s)
- Adrian Handforth
- Department of Neurology, VA Greater Los Angeles Health Care System, Los Angeles, CA 90073, USA.
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Zhou J, Pfaff DW, Chen G. Sex differences in estrogenic regulation of neuronal activity in neonatal cultures of ventromedial nucleus of the hypothalamus. Proc Natl Acad Sci U S A 2005; 102:14907-12. [PMID: 16204378 PMCID: PMC1253608 DOI: 10.1073/pnas.0507440102] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Estrogenic effects have been implicated in sexual differentiation of brain and behavior, in part by affecting neuronal activity in the ventromedial nucleus of the hypothalamus (VMN). We report here a remarkable sex difference in estrogenic regulation of neuronal activity in male vs. female neural networks. Spontaneous synaptic currents originating from a population of neurons were recorded in primary VMN cultures using the whole-cell patch-clamp technique. Treatment with 17beta-estradiol (E2, 10 nM) for 24 h induced opposite effects in the two sexes: the frequency of spontaneous synaptic events decreased significantly in neurons derived from males but increased in those from females. Interestingly, the 24-hour E2 effect was partially reversed by an acute application (5 min) of a second dose of E2 (10 nM), suggesting an interaction between extended (24-hr) and acute (5-min) effects of E2 in VMN neurons. To understand the underlying mechanism of this sexually dimorphic action of E2, we analyzed the E2 effect on GABAergic neurotransmission by recording miniature inhibitory postsynaptic currents. After 24-hour E2 treatment, both the amplitude and frequency of miniature inhibitory postsynaptic currents increased in neurons derived from males but decreased in those from females. These results suggest that E2-induced changes in GABAergic inhibition could at least partially explain E2 effects on neuronal activity. We conclude that E2 may have sexually dimorphic effects on the synaptic output of VMN neurons by modulating GABAergic neurotransmission.
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Affiliation(s)
- Jin Zhou
- Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, NY 10021, USA.
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27
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Wolfe CA, Van Doren M, Walker HJ, Seney ML, McClellan KM, Tobet SA. Sex differences in the location of immunochemically defined cell populations in the mouse preoptic area/anterior hypothalamus. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 157:34-41. [PMID: 15939083 DOI: 10.1016/j.devbrainres.2005.03.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Revised: 03/02/2005] [Accepted: 03/03/2005] [Indexed: 12/19/2022]
Abstract
The preoptic area/anterior hypothalamus (POA/AH) is sexually dimorphic in many vertebrates. We have defined specific cell populations within the POA/AH using immunocytochemical markers for estrogen receptor beta (ERbeta) and the R1 subunit of the GABA(B) receptor (GABA(B)R1). Our previous finding of sex differences in cell migration in this region in embryonic day 15 mice led us to examine sex differences in the location or size of chemically identified cell groups. At embryonic day 17 (E17), cells containing immunoreactive (ir) ERbeta in females were located more dorsal and lateral than those in males. In contrast to this positional sex difference seen at E17, ERbeta expression at P0 and adulthood showed a sex difference in cell number and area of immunoreactivity with a higher expression of ERbeta in males than females. Furthermore, in animals that were genetically deprived of gonadal and adrenal hormones by virtue of a disrupted gene coding for steroidogenic factor 1, cells containing ir ERbeta followed a female phenotype for location at E17 and a female phenotype for number of ir cells at P0 regardless of genetic sex, suggesting that circulating hormones may be influencing cell position in the POA/AH. A second phenotypically identified cell group containing ir GABA(B)R1 also had a sex difference in cell positions at E17. Females expressed GABA(B)R1 in cells with a more dorsal position than in males. These results provide support for the suggestion that sex differences in cellular organization in the developing hypothalamus arise from sex differences in cell migration.
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Affiliation(s)
- Cory A Wolfe
- Department of Biomedical Sciences, Colorado State University, 1680 Campus Delivery, Fort Collins, CO 80523, USA
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28
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Rout UK. Alcohol, GABA receptors, and neurodevelopmental disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 71:217-37. [PMID: 16512353 DOI: 10.1016/s0074-7742(05)71010-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Ujjwal K Rout
- Department of Surgery, Division of Pediatric Surgery, Research Laboratories University of Mississippi Medical Center, Jackson 39216, USA
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Davis AM, Seney ML, Stallings NR, Zhao L, Parker KL, Tobet SA. Loss of steroidogenic factor 1 alters cellular topography in the mouse ventromedial nucleus of the hypothalamus. ACTA ACUST UNITED AC 2004; 60:424-36. [PMID: 15307147 DOI: 10.1002/neu.20030] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Knockout (KO) mice lacking the orphan nuclear receptor steroidogenic factor 1 (SF-1) exhibit marked structural abnormalities of the ventromedial nucleus of the hypothalamus (VMH). In this study, we sought to determine the molecular mechanisms underlying the VMH abnormalities. To trace SF-1-expressing neurons, we used a SF-1/enhanced green fluorescent protein (eGFP) transgene. Although the total numbers of eGFP-positive cells in wild-type (WT) and SF-1 KO mice were indistinguishable, cells that normally localize precisely within the VMH were scattered more diffusely in adjacent regions in SF-1 KO mice. This abnormal distribution is likely due to the loss of SF-1 expression in VMH neurons rather than secondary effects of deficient steroidogenesis, as redistribution also was seen in mice with a CNS-specific KO of SF-1. Thus, the absence of SF-1 alters the distribution of cells that normally form the VMH within the mediobasal hypothalamus. Consistent with this model, the hypothalamic expression patterns of the transcription factors islet-1 and nkx2.1 also were displaced in SF-1 KO mice. Independent of gene expression, birthdate analyses further suggested that cells with earlier birthdates were affected more severely by the loss of SF-1 than were later born cells. We conclude that the absence of SF-1 causes major changes in cellular arrangement within and around the developing VMH that result from altered cell migration.
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Affiliation(s)
- Aline M Davis
- Framingham State College, Framingham, Massachusetts 01701, USA
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30
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Bäckberg M, Collin M, Ovesjö ML, Meister B. Chemical coding of GABA(B) receptor-immunoreactive neurones in hypothalamic regions regulating body weight. J Neuroendocrinol 2003; 15:1-14. [PMID: 12535164 DOI: 10.1046/j.1365-2826.2003.00843.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gamma-aminobutyric acid (GABA) interacts with hypothalamic neuronal pathways regulating feeding behaviour. GABA has been reported to stimulate feeding via both ionotropic GABA(A) and metabotropic GABA(B) receptors. The functional form of the GABA(B) receptor is a heterodimer consisting of GABA(B) receptor-1 (GABA(B)R1) and GABA(B) receptor-2 (GABA(B)R2) proteins. Within the heterodimer, the GABA-binding site is localized to GABA(B)R1. In the present study, we used an antiserum to the GABA(B)R1 protein in order to investigate the cellular localization of GABA(B)R1-immunoreactive neurones in discrete hypothalamic regions implicated in the control of body weight. The colocalization of GABA(B)R1 immunoreactivity with different chemical messengers that regulate food intake was analysed. GABA(B)R1-immunoreactive cell bodies were found in the periventricular, paraventricular (PVN), supraoptic, arcuate, ventromedial hypothalamic, dorsomedial hypothalamic, tuberomammillary nuclei and lateral hypothalamic area (LHA). Direct double-labelling showed that glutamic acid decarboxylase (GAD)-positive terminals were in close contact with GABA(B)R1-containing cell bodies located in all these regions. In the ventromedial part of the arcuate nucleus, GABA(B)R1-immunoreactive cell bodies were found to contain neuropeptide Y, agouti-related peptide (AGRP) and GAD. In the ventrolateral part of the arcuate nucleus, GABA(B)R1-immunoreactive cell bodies were shown to contain pro-opiomelanocortin and cocaine- and amphetamine-regulated transcript. In the LHA, GABA(B)R1 immunoreactivity was present in both melanin-concentrating hormone- and orexin-containing cell populations. In the tuberomammillary nucleus, GABA(B)R1-immunoreactive cell bodies expressed histidine decarboxylase, a marker for histamine-containing neurones. In addition, GAD and AGRP were found to be colocalized in some nerve terminals surrounding GABA(B)R1-immunoreactive cell bodies in the parvocellular part of the PVN. The results may provide a morphological basis for the understanding of how GABA regulates the hypothalamic control of food intake and body weight via GABA(B) receptors.
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Affiliation(s)
- M Bäckberg
- Department of Neuroscience, The Retzius Laboratory, Karolinska Institutet, Stockholm, Sweden
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31
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Abstract
In the mature brain, GABA (gamma-aminobutyric acid) functions primarily as an inhibitory neurotransmitter. But it can also act as a trophic factor during nervous system development to influence events such as proliferation, migration, differentiation, synapse maturation and cell death. GABA mediates these processes by the activation of traditional ionotropic and metabotropic receptors, and probably by both synaptic and non-synaptic mechanisms. However, the functional properties of GABA receptor signalling in the immature brain are significantly different from, and in some ways opposite to, those found in the adult brain. The unique features of the early-appearing GABA signalling systems might help to explain how GABA acts as a developmental signal.
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Affiliation(s)
- David F Owens
- Laboratory of Molecular Biology, National Institute of Neurological Disorders and Stroke, Building 36, Room 3C09, 36 Convent Drive, Bethesda, Maryland 20892-4092, USA
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32
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Abstract
Steroid hormones dramatically influence the development of numerous sites in the nervous system. Basic mechanisms in neural development provide foci for understanding how factors related to sex can alter the ontogeny of these regions. Sex differences in neurogenesis, cell migration, cell differentiation, cell death, and synaptogenesis are being addressed. Any and all of these events serve as likely targets for genetic or gonadal steroid-dependent mechanisms throughout development. Although the majority of sexually dimorphic characteristics in brain have been described in older animals, many hormonal mechanisms that determine sexually differentiated brain characteristics occur during critical perinatal periods. Genes suggested to contribute to the development of specific hypothalamic nuclear groups have rarely been examined in the context of sex. The identification of sex differences in the expression of some of these genes may suggest early and likely transient molecular events that set the stage for later amplification by hormone actions. Sex differences in the positioning of cells in the developing hypothalamus further suggest that cell migration may be one key target for early gene actions that impact long-term susceptibility to brain sexual differentiation.
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Affiliation(s)
- Stuart A Tobet
- Department of Physiology, The Shriver Center at UMMS, 200 Trapelo Road, Waltham, MA 02452, USA.
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Davis AM, Henion TR, Tobet SA. Gamma-aminobutyric acidB receptors and the development of the ventromedial nucleus of the hypothalamus. J Comp Neurol 2002; 449:270-80. [PMID: 12115679 DOI: 10.1002/cne.10293] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Gamma-aminobutyric acid (GABA) is a highly abundant neurotransmitter in the brain and the ligand for GABA(A), GABA(B), and GABA(C) receptors. Unlike GABA(A) and GABA(C) receptors, which are chloride channels, GABA(B) receptors are G-protein linked and alter cell-signaling pathways. Electrophysiological studies have found GABA(B) receptors in cultured embryonic hypothalamus, but the distribution of these receptors remains unknown. In the present study, we examined the expression of GABA(B) receptors in the ventromedial nucleus of the hypothalamus (VMH) during embryonic mouse development. GABA(B) receptors were present in the VMH at all ages examined, from embryonic day 13 to postnatal day 6. Using a brain slice preparation, we examined the effect of GABA(B) receptor activation on cell movement in the embryonic VMH as the nucleus forms in vitro. The GABA(B) receptor agonist baclofen decreased the rate of cell movement in a dose-dependent manner. Baclofen reduced cell movement by up to 56% compared with vehicle-treated controls. The percentage of cells moving per field and the angles of cell movement were not affected. With our previous findings of GABA(A) receptor activation, it is likely that GABA influences VMH development via multiple mechanisms.
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Affiliation(s)
- Aline M Davis
- The Shriver Center, University of Massachusetts Medical School, 200 Trapelo Road, Waltham, MA 02452, USA
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