DOCSLIB.ORG

Cytochemical Localization of Alkaline Phosphatase in the Spinal Cord Ependyma of Newborn and Adult Rats

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cytochemical Localization of Alkaline Phosphatase in the Spinal Cord Ependyma of Newborn and Adult Rats ACTA HISTOCHEM. CYTOCHEM. Vol.16, No.2, 1983 CYTOCHEMICAL LOCALIZATION OF ALKALINE PHOS- PHATASE IN THE SPINAL CORD EPENDYMA OF NEWBORN AND ADULT RATS1 TAKAFUMI YOSHIOKA AND KENICHIROU INOMATA Departmentof Anatomy,Shimane Medical University,Izumo 693 Received for publication June 11, 1982 and in revised form September 7, 1982 Localization of alkaline phosphatase (AlPase) in the spinal cord ependyma of newborn and adult rats was studied using cytochemical techniques. When the reaction products were precipitated on the plasma membrane of the ependymal cells, the most intense AlPase activity was apparent on the membrane of the luminal surface of tissues from the newborn rats and this activity was also detected in the neuropil around the central canal. In the axon terminals, reaction products were precipitated on the plasma membrane of the presynapse. These observations warrant further studies on AlPase activity in the ependyma to determine if this enzyme plays a role in the mem- brane transport of the substances from the cerebrospinal fluid to the extra- cellular spaces of the spinal cord. The ependyma of the central nervous system (CNS) forms a selective barrier between the nervous tissue and the cerebrospinal fluid (CSF), and this mechanism has been termed the CSF-brain barrier (5, 12). Morphologically, the ependyma consists of a single layer of closely packed neuro- epithelial cells (or ependymal cells) (3, 7, 11). A varied number of cilia and a large number of short and slender microvilli project from the free or luminal surface of the cell. The ependymal cells form a junctional arrangement, including zonulae occludens, adhaerens and gap junctions, with adjacent cell membranes at the lateral surface. At the basal surface, a long, slender, and branching process descends into the underlying neuropil. Similar cells exist in the absorptive epithelium such as the small intestine and the kidney. It has been reported that alkaline phosphatase (AlPase) activity in these cells is localized on the plasma membrane of the luminal surface, and the possibility that AlPase activity plays an important role in the transport of the substances across the plasma membrane has been suggested (2, 8, 10, 16). There is apparently no documentation of cytochemical studies on the central canal of the spinal cord. We studied the ultrastructural localization of AlPase activity in the ependymal cell of the central canal in newborn and adult rats at the lumbar level and changes with development were observed. MATERIALS AND METHODS Albino rats at the 5th and 7th postnatal day were used for the ultracytochemical 1. This paper is dedicated to the late Prefessor Kazushige Nakamura, Department of Anatomy, Shimane Medical University. 77 78 YOSHIOKA AND INOMATA demonstration of the AlPase activity during the developmental stage and adult Wistar rats (Japan Clea) were used for studies on adult animals. All the rats were anesthetized with sodium pentobarbital (intraperitoneally) and vascular perfusion through the heart was started with physiological saline solution at room temperature for 1 min, and followed by cold 0.1 M cacodylate-buffered 1% glutaraldehyde and 2% paraformaldehyde mixture, pH 7.3-7.4, 920 mOsm. After perfusion for 15 min, the spinal cord at the lumbar level (L1-2) was removed and immersed in the same fixative for 15 min at 0-4•Ž. The materials were sectioned with a Vibra- tome at approximately 40 ƒÊm in thickness, then rinsed with cold 0.1 M cacodylate buffer, pH 7.3-7.4, containing 3% sucrose, 290 mOsm. These sections were incubated in the medium for AlPase activity (10). The omission of substrate from the complete incubation medium, substrate-free medium, and the addition of 5 mM levamisole to the complete medium were the procedures used for the control experiments. After incubation for 30 min at 37•Ž, the sections were postfixed with the cold 1% osmium tetroxide in Caulfield's buffer for 40 min, dehydrated in a series of the graded ethanol solutions, treated with propylene oxide and embedded in Spurr's medium. Thin sections for electron microscopy were obtained with a Porter-Blum MT-2 ultramicrotome or a Reichert-Jung ultracut OmU4 and stained with uranyl acetate or uranyl acetate and lead nitrate. These thin sections were examined under a HS-9 (Hitachi) electron microscope at 75 KV. RESULTS AlPase activity in the ependyma In the 5th and 7th postnatal day rats, ependymal cells had a long-oval nuclei with an irregular shape and were localized in the basal portion of the cells. Re- action products, lead phosphate, were precipitated over the entire plasma membrane of the luminal, lateral and basal surface (Fig. 1). The intense activity was demon- strated on the microvilli and the cilia at the luminal surface, the zonula adhaerens and the gap junction at the lateral surface (Figs. 1, 2a). In addition, the pinocytotic vesicles with intense activity were mainly localized in the lateral and basal portions of the cells. In organelles such as lysosome etc. AlPase activity was negative. In adult rats, AlPase activity revealed a localization pattern rather similar to that seen in the newborn rats, although the activity was comparatively weaker (Figs. 3, 4a). The nucleus of the ependymal cell was oval-shaped and was localized in the central part of the cell. Reaction products for AlPase activity in the luminal surface were evident on the plasma membrane and the activities had no homogenous pattern. However, the activity of the zonula adhaerens and the gap junction in the lateral surface did have a homogenous pattern. Here the number of the pinocytotic vesicles with AlPase activity were more numerous , as compared to findings in the newborn rats. When sections were incubated in a levamisole-containing medium , the reaction FIG. 1. AlPase activity in the ependyma of the lumbar spinal cord of 7-day-old rat . mv: microvilli. FIGS.2 a, b. The luminal surface of the ependymal cell of 5-day-old rat . (a) The plasma membranes of the microvilli (mv) and the cilia (cil) showed the intense activity of AlPase . (b) Control experiment with the substrate-free incubation medium . Note the lack of reaction product. ALPASE ACTIVITY IN EPENDYMA OF SPINAL CORD 79 80 YOSHIOKA AND INOMATA ALPASE ACTIVITY IN EPENDYMA OF SPINAL CORD 81 FIG. 5. A part of the neuropil around the central canal on the 7th postnatal day. Reaction products are apparent in the plasma membranes of many neuronal elements, including soma, dendrites and axons. of AlPase was inhibited (Fig. 4b) and no reaction occurred in specimens incubated in the substrate-free medium (Fig. 2b). AlPase activity in the neuropil around the ependyma. In the neuropil around the ependyma in both newborn and adult rats, the plasma membrane of the neuronal elements exhibited the AlPase activity (Fig. 5). Reaction products were precipitated on the plasma membrane of the neuronal soma, the dendrite, and the axolemma. The most external lammelae of the myelin in the myelinated fiber, also, showed the AlPase activity. In addition, reaction products were associated with the axon terminal (Figs. 6a, b). AlPase activity was localized on the plasma membrane of the presynapse. No difference was found in the activity of the plasma membrane and that of the membrane thickening, thereby indicating probable active sites of the synaptic zone. There was no evidence of reaction products in the control experiments. DISCUSSION Our findings of localization of intense AlPase activity on the plasma membrane FIG. 3. AlPase activity in the ependyma of adult rat. mv: microvilli FIGS.4a, b. (a) An invaginated portion of the luminal surface of the ependymal cell of an adult rat. (b) Control experiment, using the final concentration of 5 mM levamisole. Note the lack of reaction product in any structure of the luminal surface. 82 YOSHIOKA AND INOMATA FIGS. 6a, b. AlPase activity exclusively restricted to the presynaptic membrane of the axon terminal. (a) 5-day-old rat. (b) adult rat. of the luminal surface in the ependymal cell are consistent with findings in case of the absorptive epithelia, in particular the brush border of the small intestine and the proximal convoluted tubules (2, 3, 10, 16). This polarity may suggest the existence of absorptive ability in the ependymal cell at the central canal. In the ependyma of the third ventricle, the tanycytes, which show intense adenosine triphosphatase activity in the luminal microvilli, receive humoral signals by means of uptake of the substances from the CSF (6). However, little is known of the accurate role of AlPase in the ependyma because this enzyme is non-specific, although AlPase is said to be a marker-enzyme for the plasma membrane. The function of AlPase is presumably related to a selective transport of certain phosphorylated metabolites across the plasma membrane. Sakla (14) demonstrated cell migration from the wall of the central canal and the proliferative activity of the cell in the cervical region in mice for up to 30 days after birth. It is considered that enzymes depend to a considerable extent on the processes determining the normal maturation of the brain (13). Therefore, the possibility that AlPase activity may play an important role on the development of the central canal has to be considered. In addition, the number of pinocytotic vesicles showing AlPase activity in tissues from the adult rats is associated with the CSF-brain mechanism and is the result of transependymal transport. There was a remarkable AlPase activity localized on the plasma membrane of the presynapse in the neuropil around the central canal. The communication between neurons is regulated by neurotransmitters, neuromodulators and neuro- ALPASE ACTIVITY IN EPENDYMA OF SPINAL CORD 83 hormones, at the synapse (4, 16). Biochemical studies on the isolated synaptosomes showed that many neuroregulators were incorporated into the synaptosomes from the medium, and that the process of uptake required the presence of sodium or diva- lent cations such as calcium and magnesium (1, 9, 15, 17).
Load more

Recommended publications
  • Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
    Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal.
    [Show full text]
  • Differences in Neural Stem Cell Identity and Differentiation Capacity Drive Divergent Regenerative Outcomes in Lizards and Salamanders
    Differences in neural stem cell identity and differentiation capacity drive divergent regenerative outcomes in lizards and salamanders Aaron X. Suna,b,c, Ricardo Londonoa, Megan L. Hudnalla, Rocky S. Tuana,c, and Thomas P. Lozitoa,1 aCenter for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219; bMedical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; and cDepartment of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213 Edited by Robb Krumlauf, Stowers Institute for Medical Research, Kansas City, MO, and approved July 24, 2018 (received for review March 2, 2018) While lizards and salamanders both exhibit the ability to re- lizard tail regenerate (20), and the key to understanding this generate amputated tails, the outcomes achieved by each are unique arrangement of tissues is in identifying the patterning markedly different. Salamanders, such as Ambystoma mexicanum, signals involved. regenerate nearly identical copies of original tails. Regenerated lizard Both lizards and salamanders follow similar mechanisms of tails, however, exhibit important morphological differences compared tail development during embryonic development. The embryonic with originals. Some of these differences concern dorsoventral pat- spinal cord and surrounding structures are formed and patterned terning of regenerated skeletal and spinal cord tissues; regenerated by the neural tube (21, 22). The neural tube exhibits distinct + salamander tail tissues exhibit dorsoventral patterning, while re- domains: roof plate (characterized by expression of Pax7 , BMP- + + + grown lizard tissues do not. Additionally, regenerated lizard tails lack 2 , and Sox10 among others), lateral domain (Pax6 ), and floor + + characteristically roof plate-associated structures, such as dorsal root plate (Shh , FoxA2 ).
    [Show full text]
  • Reaction of Ependymal Cells to Spinal Cord Injury: a Potential Role for Oncostatin Pathway and Microglial Cells
    bioRxiv preprint doi: https://doi.org/10.1101/2021.02.12.428106; this version posted February 13, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Reaction of ependymal cells to spinal cord injury: a potential role for oncostatin pathway and microglial cells *1 *1 *1 2 2 1 R. Chevreau ​ , H Ghazale ,​ C Ripoll ,​ C Chalfouh ,​ Q Delarue ,​ A.L. Hemonnot ,​ H 1 ​ 3 ​ 4 ​ 5 ​ *2 ​ *1 ​ Hirbec ,​ S Wahane ,​ F Perrin ,​ H Noristani ,​ N Guerout ,​ JP Hugnot ​ ​ ​ ​ ​ ​ *equal contribution, listed in alphabetic order 1 Université de Montpellier, INSERM CNRS IGF, France ​ 2 Université de Rouen, France ​ 3 Departments of Neurobiology and Neurosurgery, David Geffen School of Medicine, ​ University of California, Los Angeles, Los Angeles CA 90095-1763, USA. 4 University of Montpellier, INSERM MMDN France ​ 5 Shriners Hospitals Pediatric Research Center, NY, USA ​ Abstract Ependymal cells with stem cell properties reside in the adult spinal cord around the central canal. They rapidly activate and proliferate after spinal cord injury, constituting a source of new cells. They produce neurons and glial cells in lower vertebrates but they mainly generate glial cells in mammals. The mechanisms underlying their activation and their glial-biased differentiation in mammals remain ill-defined. This represents an obstacle to control these cells. We addressed this issue using RNA profiling of ependymal cells before and after injury. We found that these cells activate STAT3 and ERK/MAPK signaling during injury and downregulate cilia-associated genes and FOXJ1, a central transcription factor in ciliogenesis.
    [Show full text]
  • Wnt/Β-Catenin Signaling Regulates Ependymal Cell Development and Adult Homeostasis
    Wnt/β-catenin signaling regulates ependymal cell development and adult homeostasis Liujing Xinga, Teni Anbarchiana, Jonathan M. Tsaia, Giles W. Plantb, and Roeland Nussea,c,1 aDepartment of Developmental Biology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305; bDepartment of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305; and cHoward Hughes Medical Institute, Stanford, CA 94305 Contributed by Roeland Nusse, May 22, 2018 (sent for review February 23, 2018; reviewed by Bin Chen and Samuel Pleasure) In the adult mouse spinal cord, the ependymal cell population that precursors and are present before the onset of neurogenesis. surrounds the central canal is thought to be a promising source of They give rise to radial glial cells, which then become the pre- quiescent stem cells to treat spinal cord injury. Relatively little is dominant progenitors during gliogenesis (19, 20). Eventually, known about the cellular origin of ependymal cells during spinal ependymal cells are formed as the ventricle and the ventricular cord development, or the molecular mechanisms that regulate zone retract through the process of obliteration. This process is ependymal cells during adult homeostasis. Using genetic lineage accompanied by terminal differentiation and exit of radial glial tracing based on the Wnt target gene Axin2, we have character- cells from the ventricular zone (18, 19, 21–24). ized Wnt-responsive cells during spinal cord development. Our Compared with our knowledge about ependymal cells in the results revealed that Wnt-responsive progenitor cells are restricted brain, little is known about the cellular origin of spinal cord to the dorsal midline throughout spinal cord development, which ependymal cells.
    [Show full text]
  • The Fine Structure of Ependyma in the Brain Of
    THE FINE STRUCTURE OF EPENDYMA IN THE BRAIN OF THE RAT M. W. BRIGHTMAN, Ph.D., and S. L. PALAY, M.D. From the Laboratory of Neuroanatomical Sciences, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Maryland. Dr. Palay's present address is Department of Anatomy, Harvard Medical School, Boston ABSTRACT The ciliated ependyma of the rat brain consists of a sheet of epithelial cells, the luminal surface of which is reflected over ciliary shafts and numerous evaginations of irregular di- mensions. The relatively straight lateral portions of the plasmalemma of contiguous cells are fused at discrete sites to form five-layered junctions or zonulae occludentes which obliterate the intercellular space. These fusions occur usually at some distance below the free surface either independently or in continuity with a second intercellular junction, the zonula adhaerens. The luminal junction is usually formed by a zonula adhaerens or, occasionally, by a zonula occludens. The finely granular and filamentous cytoplasm contains supranuclear dense bodies, some of which are probably lysosomes and dense whorls of perinuclear filaments which send fascicles toward the lateral plasmalemma. The apical regions of the cytoplasm contain the basal body complexes of neighboring cilia. These complexes include a striated basal foot and short, non-striated rootlets emanating from the wall of each basal body. The rootlets end in a zone of granules about the proximal region of the basal body, adjacent to which may lie a striated mass of variable shape. All components of the basal body complex of adjacent cilia are independent of each other.
    [Show full text]
  • Transcriptional Control of Hypothalamic Tanycyte
    TRANSCRIPTIONAL CONTROL OF HYPOTHALAMIC TANYCYTE DEVELOPMENT By Ana Lucia Miranda-Angulo A dissertation submitted to the Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy Baltimore, Maryland March 2013 © 2013 Ana Lucia Miranda-Angulo All Rights Reserved Abstract The wall of the ventral third ventricle is composed of two distinct cell populations; tanycytes and ependymal cells. Tanycytes support several hypothalamic functions but little is known about the transcriptional network which regulates their development. We explored the developmental expression of multiple transcription factors by in situ hybridization and found that the retina and anterior neural fold homeobox transcription factor (Rax) was expressed in both ventricular progenitors of the hypothalamic primordium and differentiating tanycytes. Rax is known to participate in retina and hypothalamus development but nothing is known about its function in tanycytes. To explore the role of Rax in hypothalamic tanycyte development we generated Rax haploinsufficient mice. These mice appeared grossly normal, but careful examination revealed a thinning of the third ventricular wall and reduction of tanycyte and ependymal markers. These experiments show that Rax is required for tanycyte and ependymal cell progenitor proliferation and/or survival. Rax haploinsufficiency also resulted in ectopic presence of ependymal cells in the α2 tanycytic zone were few ependymal cells are normally found. Thus, the presence of ependymal cell in this zone suggests that Rax was required for α2 tanycyte differentiation. These changes in the ventricular wall were associated with reduced diffusion of Evans Blue tracer from the ventricle to the hypothalamic parenchyma. Furthermore, we have provided in vivo and in vitro evidence suggesting that RAX protein is secreted by tanycytes, and subsequently internalized by adjacent and distal cells.
    [Show full text]
  • Ependymal Lined Paraventricular Cerebral Cysts; a Report of Three Cases
    J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.36.4.611 on 1 August 1973. Downloaded from Journial of Neurology, Neurosurgery, and Psychiatry, 1973, 36, 611-617 Ependymal lined paraventricular cerebral cysts; a report of three cases D. C. BOUCH, I. MITCHELL, AND A. F. J. MALONEY From the Neuropathology Laboratory, Department ofPathology, University of Edinburgh and Milesmark Hospital, Dunfermline SUMMARY Three cases are reported, each with a benign ependymal-lined cyst which produced clinical signs and symptoms simulating cerebrovascular disease or cerebral neoplasm. The pathologi- cal features are described and their histogenesis discussed. Intracranial cysts lined by ependyma which are embolus with the main pathological features con- large enough to give rise to symptoms are rare. fined to the brain. Virtually all references to ependymal lined cysts BRAIN Macro The brain showed swelling of the in the literature relate to the colloid or para- Protected by copyright. physeal cyst of the third ventricle. right frontal lobe, flattening of the overlying gyri, and shift of the midline structures to the left. Occupy- This communication describes three cases in ing most of the central white matter of the right each of which a large cyst with watery content frontal lobe was a unilocular cyst (Fig. 1) compres- was found in the centrum semi-ovale. In no case sing, but not communicating with, the lateral ventricle could communication with the ventricular system and displacing the anterior corpus striatum down- be demonstrated. All presented with severe neuro- wards. The cyst, which measured 60 x 4-0 cm in logical signs and symptoms.
    [Show full text]
  • Targets Ependyma and Astrocytes in the Subventricular Zone and RMS
    Gene Therapy (2005) 12, 1503–1508 & 2005 Nature Publishing Group All rights reserved 0969-7128/05 $30.00 www.nature.com/gt RESEARCH ARTICLE Adeno-associated virus type 4 (AAV4) targets ependyma and astrocytes in the subventricular zone and RMS G Liu1,2, IH Martins1,2, JA Chiorini1,4 and BL Davidson1,2,3,5 1Program in Gene Therapy, University of Iowa, Iowa City, IA, USA; 2Department of Internal Medicine, University of Iowa, Iowa City, IA, USA; 3Department of Neurology, University of Iowa, Iowa City, IA, USA; 4National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA; and 5Department of Physiology & Biophysics, University of Iowa, Iowa City, IA, USA The subventricular zone (SVZ) is one of the neurogenic conducted on adult mice. AAV4 vectors show a characteristic niches in the adult mammalian brain. The SVZ is of interest transduction of the ependyma independent of delivery route. for studies on neurogenesis and stem cell therapy. Here, we However, AAV4 virus injected into the SVZ targeted GFAP report specific transduction of ependyma and/or astrocytes positive astrocytes forming the glial tube in the SVZ and by recombinant adeno-associated virus type 4 (AAV4) viral rostral migratory stream (RMS). Our results introduce AAV4 vectors. AAV4 vectors encoding b-galactosidase or eGFP as a new tool by which to manipulate glial cells in the RMS. were injected into the lateral ventricles of neonatal and adult Gene Therapy (2005) 12, 1503–1508. doi:10.1038/ C57BL/6 mouse brains. In addition, SVZ injections
    [Show full text]
  • 26 April 2010 TE Prepublication Page 1 Nomina Generalia General Terms
    26 April 2010 TE PrePublication Page 1 Nomina generalia General terms E1.0.0.0.0.0.1 Modus reproductionis Reproductive mode E1.0.0.0.0.0.2 Reproductio sexualis Sexual reproduction E1.0.0.0.0.0.3 Viviparitas Viviparity E1.0.0.0.0.0.4 Heterogamia Heterogamy E1.0.0.0.0.0.5 Endogamia Endogamy E1.0.0.0.0.0.6 Sequentia reproductionis Reproductive sequence E1.0.0.0.0.0.7 Ovulatio Ovulation E1.0.0.0.0.0.8 Erectio Erection E1.0.0.0.0.0.9 Coitus Coitus; Sexual intercourse E1.0.0.0.0.0.10 Ejaculatio1 Ejaculation E1.0.0.0.0.0.11 Emissio Emission E1.0.0.0.0.0.12 Ejaculatio vera Ejaculation proper E1.0.0.0.0.0.13 Semen Semen; Ejaculate E1.0.0.0.0.0.14 Inseminatio Insemination E1.0.0.0.0.0.15 Fertilisatio Fertilization E1.0.0.0.0.0.16 Fecundatio Fecundation; Impregnation E1.0.0.0.0.0.17 Superfecundatio Superfecundation E1.0.0.0.0.0.18 Superimpregnatio Superimpregnation E1.0.0.0.0.0.19 Superfetatio Superfetation E1.0.0.0.0.0.20 Ontogenesis Ontogeny E1.0.0.0.0.0.21 Ontogenesis praenatalis Prenatal ontogeny E1.0.0.0.0.0.22 Tempus praenatale; Tempus gestationis Prenatal period; Gestation period E1.0.0.0.0.0.23 Vita praenatalis Prenatal life E1.0.0.0.0.0.24 Vita intrauterina Intra-uterine life E1.0.0.0.0.0.25 Embryogenesis2 Embryogenesis; Embryogeny E1.0.0.0.0.0.26 Fetogenesis3 Fetogenesis E1.0.0.0.0.0.27 Tempus natale Birth period E1.0.0.0.0.0.28 Ontogenesis postnatalis Postnatal ontogeny E1.0.0.0.0.0.29 Vita postnatalis Postnatal life E1.0.1.0.0.0.1 Mensurae embryonicae et fetales4 Embryonic and fetal measurements E1.0.1.0.0.0.2 Aetas a fecundatione5 Fertilization
    [Show full text]
  • Correlated Electrophysiology and Morphology of the Ependyma in Rat Hypothalamus
    The Journal of Neuroscience, October 1988, 8(10): 3691-3702 Correlated Electrophysiology and Morphology of the Ependyma in Rat Hypothalamus C. R. Jarvisa and Ft. D. Andrew Department of Anatomy, Queen’s University, Kingston, Ontario, Canada K7L 3N6 The ependyma lines the ventricular system of the vertebrate and may therefore have similar functions. In the hypothal- brain and spinal cord. Although its embryology and mor- amus, ependyma probably take up K+ released from adja- phology have been studied extensively, little is known of its cent endocrine neurons and shunt it to the ventricular space. physiological properties, particularly in mammals. Tany- cytes are modified ependymal cells that are found predom- The ventricular system of the brain and spinal cord is lined by inantly lining the floor of the third ventricle, overlying the the ependyma, a singlelayer of squamous,cuboidal, or columnar median eminence. Their processes accompany and enwrap epithelial cells. Some ependymal cells, termed tanycytes, have neuroendocrine axons that course from hypothalamic nuclei long basal processesextending into the underlying neuropil. to terminals in the median eminence, but the significance of Tanycytes form the ependymal lining over the circumventricu- this interaction is not yet understood. Intracellular recording lar organs and are found scattered within the ependymal layer and injection techniques were used to study ependymal cells of the ventricles and spinal canal. Most cells lining the third and tanycytes of the rat in the hypothalamic slice preparation ventricle are cuboidal (common ependyma), although tanycytes after differentiating their respective regions morphologically. are clustered along the lateroventral wall and in the floor over- With extracellular [K+] = 6.24 mM, the mean membrane po- lying the median eminence.Tanycyte processesaccompany and tential (*SD) for common ependyma was -79.9 + 1.40 mV enwrap neuroendocrine axons that course from hypothalamic and for tanycytes, -79.5 f 1.77 mV.
    [Show full text]
  • Piggybac Transposon-Based Lineage Tracing to Reveal Ependymogenesis
    University of Connecticut OpenCommons@UConn Master's Theses University of Connecticut Graduate School 5-10-2020 Piggybac Transposon-Based Lineage Tracing to Reveal Ependymogenesis Tasnuva Nuhat Shafin University of Connecticut - Storrs, [email protected] Follow this and additional works at: https://opencommons.uconn.edu/gs_theses Recommended Citation Shafin, asnuvT a Nuhat, "Piggybac Transposon-Based Lineage Tracing to Reveal Ependymogenesis" (2020). Master's Theses. 1484. https://opencommons.uconn.edu/gs_theses/1484 This work is brought to you for free and open access by the University of Connecticut Graduate School at OpenCommons@UConn. It has been accepted for inclusion in Master's Theses by an authorized administrator of OpenCommons@UConn. For more information, please contact [email protected]. Piggybac Transposon-Based Lineage Tracing to Reveal Ependymogenesis Tasnuva Nuhat Shafin M.B.B.S., Dhaka Medical College (Dhaka University), 2016 A Thesis Submitted in the Partial Fulfillment of the Requirement for the Degree of Masters of Science at the University of Connecticut 2020 APPROVAL PAGE Masters of Science Thesis Piggybac Transposon-Based Lineage Tracing to Reveal Ependymogenesis Presented by Tasnuva Nuhat Shafin, MBBS Major Advisor: _____________________________________ Joanne Conover, PhD Associate Advisor: ______________________________________ Joseph LoTurco, PhD Associate Advisor: ______________________________________ Anastasios Tzingounis, PhD University of Connecticut 2020 ii Acknowledgements My time at the University of Connecticut has been so valuable to me due to the support and guidance of the great people I’ve been surrounded by. My deepest gratitude to Dr. Joanne Conover for her direction, patience, and thoughtful discussion that has helped me grow and expand my skills as a scientist. I’d also like to thank my committee members, Dr.
    [Show full text]
  • Immune Surveillance in the Central Nervous System
    REVIEW FOCUS ON NEURO-IMMUNE INTERACTIONS Immune surveillance in the central nervous system Shalina S Ousman1–3 & Paul Kubes4–6 The CNS, which consists of the brain and spinal cord, is continuously monitored by resident microglia and blood-borne immune cells such as macrophages, dendritic cells and T cells to detect for damaging agents that would disrupt homeostasis and optimal functioning of these vital organs. Further, the CNS must balance between vigilantly detecting for potentially harmful factors and resolving any immunological responses that in themselves can create damage if left unabated. We discuss the physiological roles of the immune sentinels that patrol the CNS, the molecular markers that underlie their surveillance duties, and the consequences of interrupting their functions following injury and infection by viruses such as JC virus, human immunodeficiency virus, herpes simplex virus and West Nile virus. Although the CNS lacks lymphatics, displays low levels of major presentation should a florid inflammatory response be necessary2. Here, histocompatibility complex (MHC) molecules and is uniquely we summarize knowledge of how microglia and peripheral immune shielded from free diffusion of molecular and cellular components cells participate in promoting physiological balance and protection of by the blood-brain barrier (BBB) and the blood–cerebrospinal fluid the normal CNS and how interruption of immune patrol of the brain (CSF) barrier, the immune response in the brain can be impressive and spinal cord can lead to and/or augment disease and injury. if not spectacular, as is the case in meningitis. By contrast, loss of immunity is often highlighted by cerebral infections. To protect this Microglia mediate surveillance and homeostasis in the CNS vital system, the healthy brain and spinal cord are under continual Even though they share surface markers with hematogenously derived immune surveillance to detect and eliminate potential mediators of macrophages3, it has recently been shown that one subset of microglia Nature America, Inc.
    [Show full text]