DOCSLIB.ORG

Hydrocephalus Induced by Immunological Blockage of the Subcommissural Organ–Reissner’S Fiber (RF) Complex by Maternal Transfer of Anti-RF Antibodies

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hydrocephalus Induced by Immunological Blockage of the Subcommissural Organ–Reissner’S Fiber (RF) Complex by Maternal Transfer of Anti-RF Antibodies Exp Brain Res (2000) 135:41–52 DOI 10.1007/s002210000474 RESEARCH ARTICLE K. Vio · S. Rodríguez · E.H. Navarrete J.M. Pérez-Fígares · A.J. Jiménez · E.M. Rodríguez Hydrocephalus induced by immunological blockage of the subcommissural organ–Reissner’s fiber (RF) complex by maternal transfer of anti-RF antibodies Received: 14 February 2000 / Accepted: 15 May 2000 / Published online: 9 September 2000 © Springer-Verlag 2000 Abstract Stenosis of the cerebral aqueduct seems to Introduction be a key event for the development of congenital hydrocephalus. The causes of such a stenosis are not Congenital hydrocephalus has been reported to occur not well known. Overholser et al. in 1954 (Anat Rec only in humans, but also in several laboratory mammals. 120:917–933) proposed the hypothesis that a dysfunction The latter have been used to investigate certain aspects of the subcommissural organ (SCO) leads to aqueductal of this disease (cf. Pérez-Fígares et al. 1998). One of the stenosis and congenital hydrocephalus. The SCO is a unsolved issues is how much the stenosis and/or the brain gland, located at the entrance of the cerebral aque- complete obliteration of the cerebral aqueduct is in- duct, that secretes glycoproteins into the cerebrospinal volved in the pathogeneses of congenital hydrocephalus. fluid that, upon release, assemble into a fibrous structure Indeed, the disease may course either with a normal, or a known as Reissner’s fiber (RF). By the permanent addi- stenosed, or an obliterated aqueduct. It has even been tion of new molecules to its rostral end, RF grows and postulated that when aqueductal stenosis does occur it is extends along the aqueduct, fourth ventricle, and central due to a secondary effect that results from hydrocepha- canal of the spinal cord. The immunological blockage of lus, and is not the cause of it (Borit 1976; Williams the SCO-RF complex has been used to test Overholser’s 1973) However, most reports support the view that ste- hypothesis. The following was the sequence of events nosis of the aqueduct is a key event for the development occurring in pregnant rats that had been immunized with of congenital hydrocephalus (Borit 1976; Bruni et al. RF glycoproteins: the mother produced anti-RF antibod- 1988; Jones and Bucknall 1988; Jones et al. 1987). ies and transferred them to the fetus through the placenta The causes of such a stenosis, however, are not well and to the pup through the milk, and the antibodies known. Viral infections occurring in several species are reached the brain of the fetus and pup and blocked the known to sequentially trigger ependymal damage, an SCO-RF complex. This resulted in a permanent absence aqueductal stenosis, and a non-communicating hydro- of RF that was followed by stenosis of the cerebral aque- cephalus (Margolis and Kilham 1969; Nielsen and duct, and then by the appearance of hydrocephalus. The Baringer 1972). Wong et al. (1995) have suggested that latter was patent until the end of the 6-month observation N-CAM L1, a molecule inducing cell adhesion, is in- period. The chronic hydrocephalic state appeared, in volved in the differentiation of the ependymal lining; the turn, to induce new alterations of the SCO. It is conclud- same authors have shown that in humans a mutation in ed that a selective immunological knock out of the L1 leads to a congenital hydrocephalus with stenosis of SCO-RF complex leads to hydrocephalus. the cerebral aqueduct (Wong et al. 1995). Recently, a transgenic mouse model with a mutation in the L1 gene Key words Aqueduct stenosis · Hydrocephalus · has been obtained (Dahme et al. 1997). These mice had a Immunoneutralization · Subcommissural organ · Rat hydrocephalus characterized by a dilatation of the lateral and fourth ventricles; the cerebral aqueduct was not ste- K. Vio · S. Rodríguez · E.H. Navarrete · E.M. Rodríguez (✉) nosed but it was irregularly shaped (Dahme et al. 1997; Instituto de Histlogía y Patología, Facultad de Medicina, Fransen et al. 1998). This latter abnormality was consid- Universidad Austral de Chile, Valdivia, Chile ered as a probable cause of the dilatation of the lateral e-mail: [email protected] Tel.: +56-63-221207, Fax: +56-63-221604 ventricles (Fransen et al. 1998). An old hypothesis proposed by Overholser et al. J.M. Pérez-Fígares · A.J. Jiménez Departamento de Biología Celular y Genética, (1954), still valid as a working hypothesis, involved the Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, subcommissural organ (SCO) in the pathogeneses of Spain aqueductal stenosis (see below). The SCO is a brain 42 gland located in a key position, the roof of the third may be impaired when antibodies against the SCO secre- ventricle, at the entrance of the cerebral aqueduct tion reach the CSF. (Rodríguez et al. 1992, 1998). The SCO secretes into The immunological blockage of the SCO-RF complex the ventricle glycoproteins of high molecular weight during the whole of fetal life and the early postnatal (Nualart et al. 1991), that upon release condense into a weeks has been obtained by the transplacental delivery fibrous structure known as Reissner’s fiber (RF). As new to the fetuses, and through the milk to the pups, of spe- molecules are added to its rostral end, RF grows at a cific antibodies against the SCO secretory proteins. constant rate, and extends along the aqueduct, fourth Some of these animals died during the first 3 postnatal ventricle, and central canal of the spinal cord (Rodríguez weeks; those who survived displayed a rise in the CSF et al. 1992, 1998). The SCO differentiates early in ontog- concentration of several amines (Rodríguez et al. 1999). eny (Schöbitz et al. 1986) and remains fully active dur- The aim of the present investigation was to use this ani- ing the fetal life (Oksche 1969). In the human, the SCO mal model in order to test the hypothesis of Overholser differentiates during the 2nd month of pregnancy and et al. (1954) that a dysfunction of the SCO may lead to a reaches a maximal development during the second half congenital hydrocephalus. Indeed, during the first post- of the embryonic life (Oksche 1969; Rodríguez et al. natal weeks, the rats with a permanent blockage of the 1992, 1998). The human SCO appears to secrete glyco- SCO-RF complex by maternal delivery of antibodies de- proteins into the CSF that do not aggregate in the form velop hydrocephalus. of an RF, but remain soluble in the CSF (Rodríguez et al. 1993). Overholser et al. (1954) postulated that: (1) the secre- Materials and methods tion of the SCO released into the rostral end of the aque- duct during fetal life prevents the closure of the cerebral Animals aqueduct, thus facilitating the free circulation of CSF be- Maternal transfer of antibodies tween the third and the fourth ventricles, and (2) a dys- function of the SCO might lead to the aqueductal steno- The model of maternal delivery of antibodies against RF glyco- sis and a congenital hydrocephalus. This hypothesis has proteins, recently developed in our laboratory (Rodríguez et al. 1999), was used in the present investigation. This experimental gained support from recent findings. Maldevelopment of design, that has been explained in detail elsewhere (Rodríguez the SCO induced by X-irradiation during fetal life is fol- et al. 1999), will be briefly described. Twenty female Sprague- lowed by stenosis of the aqueduct and then by congenital Dawley rats were immunized with the constituent glycoproteins of hydrocephalus (Takeuchi and Takeuchi 1986). Accord- RF. The first immunization was with 100 µg RF glycoproteins emulsified with complete Freund’s adjuvant injected subcutane- ing to Takeuchi et al. (1987), the mouse MT/HokIdr ously. The second immunization was with 50 µg RF glycoproteins lacks an SCO and develops a congenital hydrocephalus. emulsified with incomplete Freund’s adjuvant injected into multi- Hydrocephalic SUMS/np mice have been reported to ple subcutaneous sites 17 days after the first immunization. For have aqueductal stenosis and a small SCO (Bruni et al. the third immunization, 17 days after the second immunization 1988; Jones et al. 1987). A drastic reduction in the size 50 µg RF glycoproteins were injected into the peritoneum using phosphate-buffered saline as vehicle. Seven days after the second of the SCO has been reported in rats CWS/Idr (Takeuchi immunization, the immunized rats were mated overnight; fecunda- et al. 1988) and H-Tx (Jones and Bucknall 1988) with tion occurred in all of them. Under this experimental condition, congenital hydrocephalus, and in rats with a postnatally mothers transferred antibodies against RF glycoproteins to the fe- induced hydrocephalus (Irigoin et al. 1990). The SCO of tuses through the placenta, and to the pups through the milk. Thus, during the key period extending from E-12, when the placenta is the mutant mouse hyh, that develops a severe congenital fully developed, to the end of the 1st postnatal month, when the hydrocephalus, shows signs of increased secretory activ- pups stop suckling milk, the animals were permanently provided ity, and releases to the stenosed aqueduct a material that with anti-RF antibodies (Rodríguez et al. 1999). These authors aggregates, but it does not form an RF (Pérez-Fígares et have confirmed that the transferred antibodies actually reached the blood and the CSF of the fetuses and pups, and blocked RF forma- al. 1998). Severe morphological alterations of the SCO tion during the first 2 months of life. The 20 immunized mothers of hydrocephalic human fetuses have been reported delivered 180 pups; 18% died during the first 3 postnatal weeks. (Castañeyra-Perdomo et al. 1994). Thus, in all species One hundred and seven of the 148 surviving pups were divided in- developing congenital hydrocephalus, in which the SCO- to 14 groups (about 10 pups per group), which were processed for RF complex has been investigated, changes in such a light microscopy at birth and at the ages of 1, 2, 3, 4, 5, 6, 7, 8, and 11 weeks and 3, 4, 5, and 6 months.
Load more

Recommended publications
  • Transcription of SCO-Spondin in the Subcommissural Organ: Evidence for Down-Regulation Mediated by Serotonin
    Molecular Brain Research 129 (2004) 151–162 www.elsevier.com/locate/molbrainres Research report Transcription of SCO-spondin in the subcommissural organ: evidence for down-regulation mediated by serotonin Hans G. Richtera,*, Marı´a M. Tome´b, Carlos R. Yulisa, Karin J. Vı´oa, Antonio J. Jime´nezb, Jose´M.Pe´rez-Fı´garesb, Esteban M. Rodrı´gueza aInstituto de Histologı´a y Patologı´a, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile bDepartamento de Biologı´a Celular y Gene´tica, Facultad de Ciencias, Universidad de Ma´laga, Spain Accepted 7 July 2004 Available online 13 August 2004 Abstract The subcommissural organ (SCO) is a brain gland located in the roof of the third ventricle that releases glycoproteins into the cerebrospinal fluid, where they form a structure known as Reissner’s fiber (RF). On the basis of SCO-spondin sequence (the major RF glycoprotein) and experimental findings, the SCO has been implicated in central nervous system development; however, its function(s) after birth remain unclear. There is evidence suggesting that SCO activity in adult animals may be regulated by serotonin (5HT). The use of an anti-5HT serum showed that the bovine SCO is heterogeneously innervated with most part being poorly innervated, whereas the rat SCO is richly innervated throughout. Antibodies against serotonin receptor subtype 2A rendered a strong immunoreaction at the ventricular cell pole of the bovine SCO cells and revealed the expected polypeptides in blots of fresh and organ-cultured bovine SCO. Analyses of organ-cultured bovine SCO treated with 5HT revealed a twofold decrease of both SCO-spondin mRNA level and immunoreactive RF glycoproteins, whereas no effect on release of RF glycoproteins into the culture medium was detected.
    [Show full text]
  • The Connexions of the Amygdala
    J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.2.137 on 1 April 1965. Downloaded from J. Neurol. Neurosurg. Psychiat., 1965, 28, 137 The connexions of the amygdala W. M. COWAN, G. RAISMAN, AND T. P. S. POWELL From the Department of Human Anatomy, University of Oxford The amygdaloid nuclei have been the subject of con- to what is known of the efferent connexions of the siderable interest in recent years and have been amygdala. studied with a variety of experimental techniques (cf. Gloor, 1960). From the anatomical point of view MATERIAL AND METHODS attention has been paid mainly to the efferent connexions of these nuclei (Adey and Meyer, 1952; The brains of 26 rats in which a variety of stereotactic or Lammers and Lohman, 1957; Hall, 1960; Nauta, surgical lesions had been placed in the diencephalon and and it is now that there basal forebrain areas were used in this study. Following 1961), generally accepted survival periods of five to seven days the animals were are two main efferent pathways from the amygdala, perfused with 10 % formol-saline and after further the well-known stria terminalis and a more diffuse fixation the brains were either embedded in paraffin wax ventral pathway, a component of the longitudinal or sectioned on a freezing microtome. All the brains were association bundle of the amygdala. It has not cut in the coronal plane, and from each a regularly spaced generally been recognized, however, that in studying series was stained, the paraffin sections according to the Protected by copyright. the efferent connexions of the amygdala it is essential original Nauta and Gygax (1951) technique and the frozen first to exclude a contribution to these pathways sections with the conventional Nauta (1957) method.
    [Show full text]
  • Thalamus and Hypothalamus
    DIENCEPHALON: THALAMUS AND HYPOTHALAMUS M. O. BUKHARI 1 DIENCEPHALON: General Introduction • Relay & integrative centers between the brainstem & cerebral cortex • Dorsal-posterior structures • Epithalamus • Anterior & posterior paraventricular nuclei • Habenular nuclei – integrate smell & emotions • Pineal gland – monitors diurnal / nocturnal rhythm • Habenular Commissure • Post. Commissure • Stria Medullaris Thalami • Thalamus(Dorsal thalamus) • Metathalamus • Medial geniculate body – auditory relay • Lateral geniculate body – visual relay Hypothalamic sulcus • Ventral-anterior structure • Sub-thalums (Ventral Thalamus) • Sub-thalamic Nucleus • Zona Inserta • Fields of Forel • Hypothalamus M. O. BUKHARI 2 Introduction THE THALAMUS Location Function External features Size Interthalamic 3 cms length x 1.5 cms breadth adhesion Two ends Anterior end– Tubercle of Thalamus Posterior end– Pulvinar – Overhangs Med & Lat.Gen.Bodies, Sup.Colliculi & their brachia Surfaces Sup. Surface – Lat. Part forms central part of lat. Vent. Med. Part is covered by tela choroidea of 3rd vent. Inf. Surface - Ant. part fused with subthalamus - Post. part free – inf. part of Pulvinar Med. Surface – Greater part of Lat. wall of 3rd ventricle Lat. Surface - Med.boundary of Post. Limb of internal capsule M. O. BUKHARI 3 Function of the Thalamus • Sensory relay • ALL sensory information (except smell) • Motor integration • Input from cortex, cerebellum and basal ganglia • Arousal • Part of reticular activating system • Pain modulation • All nociceptive information • Memory & behavior • Lesions are disruptive M. O. BUKHARI 4 SUBDIVISION OF THALAMUS M. O. BUKHARI 5 SUBDIVISION OF THALAMUS: WHITE MATTER OF THE THALAMUS Internal Medullary Stratum Zonale Lamina External Medullary Lamina M. O. BUKHARI 6 LATERAL MEDIAL Nuclei of Thalamus Stratum Zonale Anterior Nucleus Medial Dorsal Lateral Dorsal (Large) EXT.Med.Lam ILN Ret.N CMN VPL MGB VPM PVN Lateral Ventral Medial Ventral LGB (Small) LD, LP, Pulvinar – Dorsal Tier nuclei Hypothalamus VA, VL, VPL, VPM – Ventral Tier nuclei M.
    [Show full text]
  • Distribution of Gb3 Immunoreactivity in the Mouse Central Nervous System
    Toxins 2010, 2, 1997-2006; doi:10.3390/toxins2081997 OPEN ACCESS toxins ISSN 2072-6651 www.mdpi.com/journal/toxins Article Distribution of Gb3 Immunoreactivity in the Mouse Central Nervous System Fumiko Obata * and Tom Obrig Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St. HSFI suite 380, Baltimore, MD 21201, USA; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +1-410-706-6916; Fax: +1-410-706-2129. Received: 25 June 2010 / Accepted: 1 August 2010 / Published: 4 August 2010 Abstract: We have shown previously that neurons in the mouse spinal cord express Gb3. We show in this article that distribution of anti-Gb3-Ab reactivity occurs in many different types of neurons of different areas of the central nervous system (CNS). The immunoreactive neurons are in olfactory bulbs, cerebral cortex, hippocampus, striatum, amygdala, thalamus, hypothalamus, cerebellum, and medulla oblongata. In several different circumventricular organs where vessels do not have the blood-brain-barrier (BBB) structure, anti-Gb3-Ab is not positive for vessel structures, while neurons at these regions are positive. Also, within the ventricular area, ependymal cells in the third ventricle express Gb3, as revealed by anti-Gb3-Ab staining and intensity analysis. Keywords: globotriaosylceramide (Gb3); neuron; circumventricular organs (CVO); ependymal cells 1. Introduction In Shiga-toxin producing Escherichia coli (STEC) infections, a broad spectrum of central nervous system (CNS) symptoms occurs (abbreviations used in this article are listed in Table 1). Those symptoms include cortical blindness, poor fine-motor coordination, seizures and coma [1–13].
    [Show full text]
  • Characterization of the Human Habenula In-Vivo and Ex-Vivo at 7T
    Characterization of the Human Habenula in-vivo and ex-vivo at 7T B. Strotmann1, M. Weiss1, C. Kögler1, A. Schäfer1, R. Trampel1, S. Geyer1, A. Villringer1, and R. Turner1 1Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany Introduction: The habenula has an important controlling role within the human reward system [1,2]: positive reward is signaled by the dopamine system, whereas disappointment is linked to habenular activation. Overactivation of the lateral habenula is associated with depression [3,4]. The habenula is positioned next to the third ventricle in front of the pineal body. It is divided into a medial and lateral part, which receive input from frontal parts of the brain via the stria medullaris and project down the brainstem via the fasciculus retroflexus[5]. The habenular commissure connecting the nuclei on both hemispheres forms the habenular trigone. However, the visualization of this structure is difficult because of its rather small size of approximately 5-9 mm in diameter. Therefore, we made use of a high field strength of 7T to obtain high resolution and high contrast T1, T2* und proton density maps to visualize and determine structural subdivisions of the habenula in-vivo and ex-vivo. Methods: All experiments were performed on a 7 Tesla whole-body MR scanner (MAGNETOM 7T, Siemens Healthcare, Erlangen, Germany) using a 24 channel phased-array head coil (Nova Medical Inc, Wilmington MA, USA) for in-vivo scans, and a custom-built single channel square coil (120mm side) with the post mortem brain tissue centred inside. The study was approved by the ethics committee of the local university and informed consent was obtained.
    [Show full text]
  • Organization of The
    Ivana Pavlinac Dodig, M.D., Ph.D. 1 2 3 4 5 Hypothalamus Epithalamus Thalamus Metathalamus Subthalamus 6 Literally "between-brain„ Diencephalon is the area of the brain between the telencephalon and brainstem. It consists of the thalamus, subthalamus, hypothalamus, metathalamus, and epithalamus. Epithalamus Epithelial roof of the third ventricle, habenula, pineal body and afferent/efferent connections, including striae medullares. (dorsal) Thalamus Large mass of relay nuclei for reciprocal information flow between subcortical areas and telencephalon. Subthalamus Continuation of the tegmentum, with several nuclei including the pars reticulata of the substantia nigra. Functionally part of the basal ganglia. Hypothalamus Extends from the optic chiasm to the mammillary bodies. Contains a multitude of nuclei (e.g. suprachiasmatic nucleus, mammilary bodies) Regulatory functions of visceral, endocrine, autonomic and emotional processes: ▪ Temperature regulation ▪ Sympathetic and parasympathetic events ▪ Endocrine function of pituitary ▪ Emotional and sexual behaviour ▪ Feeding and drinking behaviour ▪ Affective processes ▪ Sleep and wake cycle 10 Anterior (supraoptic) + preoptic area Mid-level (tuberoinfundibulary) area Posterior (mammillary) area 11 Suprachiasmatic (retinal inputs for diurnal rhythms and hormone release) Preoptic nuclei (lat. and med. – endocrine and temperature regulations) Supraoptic Vazopressin Oxytocin Paraventricular 12 . Nucl. infundibularis (arcuatus) – DA (prolactine release- inhibiting hormone) .
    [Show full text]
  • Telencephalic Connections in the Pacific Hagfish (Eptatretus Stouti)
    THE JOURNAL OF COMPARATIVE NEUROLOGY 395:245–260 (1998) Telencephalic Connections in the Pacific Hagfish (Eptatretus stouti), With Special Reference to the Thalamopallial System HELMUT WICHT1* AND R. GLENN NORTHCUTT2 1Klinikum der Johann Wolfgang Goethe-Universita¨t, Dr. Senckenbergische Anatomie, Institut fu¨ r Anatomie II (Experimentelle Neurobiologie), Theodor-Stern-Kai 7, 60590 Frankfurt, Federal Republic of Germany 2Neurobiology Unit, Scripps Institution of Oceanography and Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, California 9203-0201 ABSTRACT The pallium of hagfishes (myxinoids) is unique: It consists of a superficial ‘‘cortical’’ mantle of gray matter which is subdivided into several layers and fields, but it is not clear whether or how these subdivisions can be compared to those of other craniates, i.e., lampreys and gnathostomes. The pallium of hagfishes receives extensive secondary olfactory projec- tions (Wicht and Northcutt [1993] J. Comp. Neurol. 337:529–542), but there are no experimental data on its nonolfactory connections. We therefore investigated the pallial and dorsal thalamic connections of the Pacific hagfish. Injections of tracers into the pallium labeled many cells bilaterally in the olfactory bulbs. Other pallial afferents arise from the contralateral pallium, the dorsal thalamic nuclei, the preoptic region, and the posterior tubercular nuclei. Descending pallial efferents reach the preoptic region, the dorsal thalamus, and the mesencephalic tectum but not the motor or premotor centers of the brainstem. Injections of tracers into the dorsal thalamus confirmed the presence of reciprocal thalamopal- lial connections. In addition, these injections revealed that there is no ‘‘preferred’’ pallial target for the ascending thalamic fibers; instead, ascending thalamic and secondary olfactory projections overlap throughout the pallium.
    [Show full text]
  • Differential Expression of Five Prosomatostatin Genes in the Central Nervous System of the Catshark Scyliorhinus Canicula
    bioRxiv preprint doi: https://doi.org/10.1101/823187; this version posted October 30, 2019. 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. Differential expression of five prosomatostatin genes in the central nervous system of the catshark Scyliorhinus canicula Daniel Sobrido-Cameán1, Herve Tostivint2, Sylvie Mazan3, María Celina Rodicio1, Isabel Rodríguez-Moldes1, Eva Candal1, Ramón Anadón1,*, Antón Barreiro-Iglesias1,* 1Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain 2Molecular Physiology and Adaptation. CNRS UMR7221, Muséum National d’Histoire Naturelle, Paris, France 3CNRS, Sorbonne Université, Biologie intégrative des organismes marins (UMR7232- BIOM), Observatoire Océanologique, Banyuls sur Mer, France *Should be considered joint senior authors. Corresponding author: Dr. Antón Barreiro-Iglesias, Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain email: [email protected] Running title: Somatostatin transcripts in the catshark CNS. Acknowledgements: Grant sponsors: Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund 2007-2013 (Grant number: BFU-2017-87079-P to MCR). Agence Nationale de la Recherche (ANR) grant NEMO no ANR-14-CE02-0020-01 (to HT). 1 bioRxiv preprint doi: https://doi.org/10.1101/823187; this version posted October 30, 2019. 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. ABSTRACT Five prosomatostatin genes (PSST1, PSST2, PSST3, PSST5 and PSST6) have been recently identified in elasmobranchs (Tostivint, Gaillard, Mazan, & Pézeron, 2019).
    [Show full text]
  • Neural Input and Neural Control of the Subcommissural Organ
    MICROSCOPY RESEARCH AND TECHNIQUE 52:520–533 (2001) Neural Input and Neural Control of the Subcommissural Organ 1 2 1 ANTONIO J. JIME´ NEZ, * PEDRO FERNA´ NDEZ-LLEBREZ, AND JOSE MANUEL PE´ REZ-FI´GARES 1Departamento de Biologı´a Celular y Gene´tica, Facultad de Ciencias, Universidad de Ma´laga, Ma´laga, Spain 2Departamento de Biologı´a Animal, Facultad de Ciencias, Universidad de Ma´laga, Ma´laga, Spain KEY WORDS serotonin; GABA; monoamines; pineal organ ABSTRACT The neural control of the subcommissural organ (SCO) has been partially character- ized. The best known input is an important serotonergic innervation in the SCO of several mammals. In the rat, this innervation comes from raphe nuclei and appears to exert an inhibitory effect on the SCO activity. A GABAergic innervation has also been shown in the SCO of the rat and frog Rana perezi. In the rat, GABA and the enzyme glutamate decarboxylase are involved in the SCO innervation. GABA is taken up by some secretory ependymocytes and nerve terminals, coexisting with serotonin in a population of synaptic terminals. Dopamine, noradrenaline, and different neuropeptides such as LH- RH, vasopressin, vasotocin, oxytocin, mesotocin, substance P, ␣-neoendorphin, and galanin are also involved in SCO innervation. In the bovine SCO, an important number of fibers containing tyrosine hydroxylase are present, indicating that in this species dopamine and/or noradrenaline-containing fibers are an important neural input. In Rana perezi, a GABAergic innervation of pineal origin could explain the influence of light on the SCO secretory activity in frogs. A general conclusion is that the SCO cells receive neural inputs from different neurotransmitter systems.
    [Show full text]
  • 54 Cerebellarcerebral Cortex
    Cerebellar and Cerebral Cortex The cerebellar and cerebral hemispheres differ from the spinal cord in that the gray matter is located at the periphery and the white matter lies centrally. Both regions of the brain consist of an outer cortex of gray matter and a subcortical region of white matter. Cerebral Cortex The cerebral cortex is 1.5 to 4.0 mm thick and contains about 50 billion neurons plus nerve processes and supporting glial cells. In all but a few regions it is characterized by a laminated appearance. Perikarya generally are organized into five layers. Starting at the periphery of the cerebral cortex, the general organization of neurons is molecular layer (I), external granular layer (II), external pyramidal layer (III), internal granular layer (IV), internal pyramidal layer (V), and multiform layer (VI). The molecular layer (I) is a largely perikaryon-free zone just below the surface of the cortex. Neurons of similar type tend to occupy the same layer in the cerebral cortex, although each cellular layer is composed of several different cell types. For convenience of description, these neurons often are placed in two major groups: pyramidal cells and stellate or nonpyramidal cells. The perikarya of pyramidal cells are pyramidal in shape and have large apical dendrites that usually are oriented toward the surface of the cerebral cortex and enter the overlying layers; the single axons enter the subcortical white matter. They are found in layers II, III, V, and, to a lesser extent, layer VI. Very large pyramid-shaped neurons (Betz cells) are present in the internal pyramidal layer (V) of the frontal lobe.
    [Show full text]
  • CENTRAL NERVOUS SYSTEM Composed from Spinal Cord and Brain
    CENTRAL NERVOUS SYSTEM composed from spinal cord and brain SPINAL CORD − is developmentally the oldest part of CNS − is long about 45 cm in adult − fills upper 2/3 of vertebral canal cranial border at level of: foramen magnum, pyramidal decussation, exit of first pair of spinal nerves caudal border: level of L1 vertebra – medullary cone – filum terminale made by pia mater (ends at level of S2 vertebra) – spinal roots below L1 vertebra form cauda equina two enlargements: • cervical enlargement (CV – ThI): origin of nerves for upper extremity – brachial plexus • lumbosacral enlargement (LI – SII): origin of nerves for lower extremity – lumbosacral plexus Spinal segment is part of spinal cord where 1 pair of spinal n. exits. Spinal cord consists of 31 spinal segments and 31 pairs of spinal nn.: 8 cervical, 12 thoracic, 5 lumbar, 1 coccygeal. Spinal nn. leave spinal cord through íntervertebral foramens. Denticulate ligg. attach spinal segments to vertebral canal. Dermatome is part of skin innervated by 1 spinal nerve. external features: • anterior median fissure • anterolateral sulcus – exits of anterior roots of spinal nn. (laterally to anterior median fissure) • posterolateral sulcus – exits of posterior roots of spinal nn. • posterior median sulcus • posterior intermediate sulcus internal features: White matter • anterior funiculus (between anterior median fissure and anterolateral sulcus) • lateral funiculus (between anterolateral and posterolateral sulci) • posterior funiculus (between posterolateral sulcus and posterior median sulcus) is divided by posterior intermediate sulcus to: − gracile fasciculus – medial one − cuneate fasciculus – lateral one, both for sensory tracts of fine sensation White matter of spinal cord contains fibres of ascending and descending nerve tracts.
    [Show full text]
  • Central Nervous System. Sense Organs Study Guide
    CENTRAL NERVOUS SYSTEM. SENSE ORGANS STUDY GUIDE 0 Ministry of Education and Science of Ukraine Sumy State University Medical Institute CENTRAL NERVOUS SYSTEM. SENSE ORGANS STUDY GUIDE Recommended by the Academic Council of Sumy State University Sumy Sumy State University 2017 1 УДК 6.11.8 (072) C40 Authors: V. I. Bumeister, Doctor of Biological Sciences, Professor; O. S. Yarmolenko, Candidate of Medical Sciences, Assistant; O. O. Prykhodko, Candidate of Medical Sciences, Assistant Professor; L. G. Sulim, Senior Lecturer Reviewers: O. O. Sherstyuk – Doctor of Medical Sciences, Professor of Ukrainian Medical Stomatological Academy (Poltava); V. Yu. Harbuzova – Doctor of Biological Sciences, Professor of Sumy State University (Sumy) Recommended by for publication Academic Council of Sumy State University as a study guide (minutes № 11 of 15.06.2017) Central nervous system. Sense organs : study guide / C40 V. I. Bumeister, O. S. Yarmolenko, O. O. Prykhodko, L. G. Sulim. – Sumy : Sumy State University, 2017. – 173 p. ISBN 978-966-657- 694-4 This study gnide is intended for the students of medical higher educational institutions of IV accreditation level, who study human anatomy in the English language. Навчальний посібник рекомендований для студентів вищих медичних навчальних закладів IV рівня акредитації, які вивчають анатомію людини англійською мовою. УДК 6.11.8 (072) © Bumeister V. I., Yarmolenko O. S., Prykhodko O. O, Sulim L. G., 2017 ISBN 978-966-657- 694-4 © Sumy State University, 2017 2 INTRODUCTION Human anatomy is a scientific study of human body structure taking into consideration all its functions and mechanisms of its development. Studying the structure of separate organs and systems in close connection with their functions, anatomy considers a person's organism as a unit which develops basing on the regularities under the influence of internal and external factors during the whole process of evolution.
    [Show full text]