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Agoston DV. Of artificial intelligence, machine learning, and the human brain. Celebrating Miklos Palkovits' 90th birthday. Front Neuroanat 2024; 18:1374864. [PMID: 38764486 PMCID: PMC11099251 DOI: 10.3389/fnana.2024.1374864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/25/2024] [Indexed: 05/21/2024] Open
Affiliation(s)
- Denes V. Agoston
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, MD, United States
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2
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Mellott JG, Duncan S, Busby J, Almassri LS, Wawrzyniak A, Iafrate MC, Ohl AP, Slabinski EA, Beaver AM, Albaba D, Vega B, Mafi AM, Buerke M, Tokar NJ, Young JW. Age-related upregulation of dense core vesicles in the central inferior colliculus. Front Cell Neurosci 2024; 18:1396387. [PMID: 38774486 PMCID: PMC11107844 DOI: 10.3389/fncel.2024.1396387] [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: 03/05/2024] [Accepted: 04/11/2024] [Indexed: 05/24/2024] Open
Abstract
Presbycusis is one of the most prevalent disabilities in aged populations of industrialized countries. As we age less excitation reaches the central auditory system from the periphery. To compensate, the central auditory system [e.g., the inferior colliculus (IC)], downregulates GABAergic inhibition to maintain homeostatic balance. However, the continued downregulation of GABA in the IC causes a disruption in temporal precision related to presbycusis. Many studies of age-related changes to neurotransmission in the IC have therefore focused on GABAergic systems. However, we have discovered that dense core vesicles (DCVs) are significantly upregulated with age in the IC. DCVs can carry neuropeptides, co-transmitters, neurotrophic factors, and proteins destined for the presynaptic zone to participate in synaptogenesis. We used immuno transmission electron microscopy across four age groups (3-month; 19-month; 24-month; and 28-month) of Fisher Brown Norway rats to examine the ultrastructure of DCVs in the IC. Tissue was stained post-embedding for GABA immunoreactivity. DCVs were characterized by diameter and by the neurochemical profile (GABAergic/non-GABAergic) of their location (bouton, axon, soma, and dendrite). Our data was collected across the dorsolateral to ventromedial axis of the central IC. After quantification, we had three primary findings. First, the age-related increase of DCVs occurred most robustly in non-GABAergic dendrites in the middle and low frequency regions of the central IC during middle age. Second, the likelihood of a bouton having more than one DCV increased with age. Lastly, although there was an age-related loss of terminals throughout the IC, the proportion of terminals that contained at least one DCV did not decline. We interpret this finding to mean that terminals carrying proteins packaged in DCVs are spared with age. Several recent studies have demonstrated a role for neuropeptides in the IC in defining cell types and regulating inhibitory and excitatory neurotransmission. Given the age-related increase of DCVs in the IC, it will be critical that future studies determine whether (1) specific neuropeptides are altered with age in the IC and (2) if these neuropeptides contribute to the loss of inhibition and/or increase of excitability that occurs during presbycusis and tinnitus.
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Affiliation(s)
- Jeffrey G. Mellott
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
- University Hospitals Hearing Research Center, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Syllissa Duncan
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Justine Busby
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Laila S. Almassri
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
- University Hospitals Hearing Research Center, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Alexa Wawrzyniak
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Milena C. Iafrate
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Andrew P. Ohl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Elizabeth A. Slabinski
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Abigail M. Beaver
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Diana Albaba
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Brenda Vega
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Amir M. Mafi
- The Ohio State University College of Medicine, Columbus, OH, United States
| | - Morgan Buerke
- Department of Psychology, Louisiana State University, Baton Rouge, LA, United States
| | - Nick J. Tokar
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Jesse W. Young
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
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3
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Mallik B, Frank CA. Is creatine a CNS neurotransmitter? eLife 2023; 12:e91824. [PMID: 37843902 PMCID: PMC10578925 DOI: 10.7554/elife.91824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023] Open
Abstract
A range of experiments suggests that creatine, a molecule known for recycling ATP in muscle and brain tissue, may also function as a neurotransmitter in the central nervous system.
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Affiliation(s)
- Bhagaban Mallik
- Department of Anatomy and Cell Biology, University of IowaIowa CityUnited States
| | - C Andrew Frank
- Department of Anatomy and Cell Biology, University of IowaIowa CityUnited States
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4
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Blokhin VE, Pronina TS, Surkov SA, Murtazina AR, Ugryumov MV. Staining of Living Monoaminergic Neurons with 4-[4-(Dimethylamino) Styryl]-N-Methylpyridinium Iodide as a Tool for Studying Their Topography and Functions. NEUROCHEM J+ 2022. [DOI: 10.1134/s1819712422020040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Jiménez-Trejo F, Coronado-Mares I, Arriaga-Canon C, Herrera LA, Roque-Ramírez B, Chávez-Saldaña M, Rojas-Castañeda J, Cerbón M, Vigueras-Villaseñor RM. Indolaminergic System in Adult Rat Testes: Evidence for a Local Serotonin System. Front Neuroanat 2021; 14:570058. [PMID: 33679336 PMCID: PMC7933592 DOI: 10.3389/fnana.2020.570058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/07/2020] [Indexed: 11/13/2022] Open
Abstract
Serotonin (5-HT) is member of a family of indolamine molecules that participate in a wide variety of biological processes. Despite its important role in the regulation of local blood systems, little is known about the physiological function of 5-HT in reproductive organs, its functional implications, and its role in the reproduction of mammals. In the present work, we evaluated the localization and distribution of 5-HT (using histochemical analysis of indolamines) and different components of the serotoninergic system in rat testes. We detected local synthesis and degradation through immunofluorescence and western blot analyses against the TPH1, MAOA, 5-HTT, and VMAT1 serotonin transporters. We also identified the localization and distribution of the 5-HT1B, 5-HT2A, and 5-HT3A receptors. RT-PCR results showed the presence of the Tph1, Maoa, Slc6a4, and Htr3a genes in testes and in the brain stem (Tph1 was used as a negative control). High-performance liquid chromatography was used to determine the presence of 5-HT and the activity of tryptophan hydroxylase in testes homogenates in vitro. Our observations suggest that TPH1 activity and local 5-HT synthesis befall in rat testes. We propose that 5-HT could participate in the regulation of testosterone synthesis and in the spermatogenesis process via local serotoninergic system. However, more studies are needed before concluding that rat testes, or those of other mammals, contain an active form of tryptophan hydroxylase and produce 5-HT.
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Affiliation(s)
| | - Isabel Coronado-Mares
- Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | | | - Luis A Herrera
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología-Instituto de Investigaciones Biomédicas, Ciudad de México, Mexico.,Instituto Nacional de Medicina Genómica, Ciudad de México, Mexico
| | | | | | | | - Marco Cerbón
- Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
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6
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García-Ávila M, Torres X, Cercós MG, Trueta C. Specific Localization of an Auto-inhibition Mechanism at Presynaptic Terminals of Identified Serotonergic Neurons. Neuroscience 2020; 458:120-132. [PMID: 33359652 DOI: 10.1016/j.neuroscience.2020.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 11/18/2022]
Abstract
Auto-regulation mechanisms in serotonergic neurons regulate their electrical activity and secretion. Since these neurons release serotonin from different structural compartments - including presynaptic terminals, soma, axons and dendrites - through different mechanisms, autoregulation mechanisms are also likely to be different at each compartment. Here we show that a chloride-mediated auto-inhibitory mechanism is exclusively localized at presynaptic terminals, but not at extrasynaptic release sites, in serotonergic Retzius neurons of the leech. An auto-inhibition response was observed immediately after intracellular stimulation with an electrode placed in the soma, in neurons that were isolated and cultured retaining an axonal stump, where presynaptic terminals are formed near the soma, but not in somata isolated without axon, where no synaptic terminals are formed, nor in neurons in the nerve ganglion, where terminals are electrotonically distant from the soma. Furthermore, no auto-inhibition response was detected in either condition during the longer time course of somatic secretion. This shows that the auto-inhibition effects are unique to nerve terminals. We further determined that serotonin released from peri-synaptic dense-core vesicles contributes to auto-inhibition in the terminals, since blockade of L-type calcium channels, which are required to stimulate extrasynaptic but not synaptic release, decreased the amplitude of the auto-inhibition response. Our results show that the auto-regulation mechanism at presynaptic terminals is unique and different from that described in the soma of these neurons, further highlighting the differences in the mechanisms regulating serotonin release from different neuronal compartments, which expand the possibilities of a single neuron to perform multiple functions in the nervous system.
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Affiliation(s)
- Miriam García-Ávila
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, San Lorenzo Huipulco, Tlalpan 14370, Ciudad de México, Mexico.
| | - Ximena Torres
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, San Lorenzo Huipulco, Tlalpan 14370, Ciudad de México, Mexico.
| | - Montserrat G Cercós
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, San Lorenzo Huipulco, Tlalpan 14370, Ciudad de México, Mexico.
| | - Citlali Trueta
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, San Lorenzo Huipulco, Tlalpan 14370, Ciudad de México, Mexico.
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7
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Sugiyama E, Sugiura Y. [Monoamine Mapping Using Mass Spectrometry Identified New Monoamine-rich Brain Nuclei]. YAKUGAKU ZASSHI 2020; 140:979-983. [PMID: 32741871 DOI: 10.1248/yakushi.20-00012-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Monoamine neurotransmitters are released by specialized neurons that regulate behavioral and cognitive functions. Although localization of monoaminergic neurons in the brain is well known, the distribution, concentration, and kinetics of monoamines remain unclear. We used mass spectrometry imaging (MSI) for simultaneous and quantitative imaging of endogenous monoamines to generate a murine brain atlas of serotonin (5-HT), dopamine (DA), and norepinephrine (NE) levels. We observed several nuclei rich in both 5-HT and a catecholamine (DA or NE). Additionally, we analyzed de novo monoamine synthesis or fluctuations in those nuclei. We propose that MSI is a useful tool to gain deeper understanding of associations among the localization, levels, and turnover of monoamines in different brain areas and their role in inducing behavioral changes.
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Affiliation(s)
- Eiji Sugiyama
- Department of Biochemistry, Keio University School of Medicine
| | - Yuki Sugiura
- Department of Biochemistry, Keio University School of Medicine
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8
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Boullerne AI, Foley P, Turner AJ, Johnston GAR, Beart PM. The origins and early history of neurochemistry and its societies. J Neurochem 2019; 152:8-28. [PMID: 31357242 DOI: 10.1111/jnc.14839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/08/2019] [Accepted: 07/25/2019] [Indexed: 11/26/2022]
Abstract
At the 2017 joint meeting of the International Society for Neurochemistry (ISN) and the European Society for Neurochemistry, 150 years of neurochemistry - the 50th anniversary of ISN, 40 years of European Society for Neurochemistry, and 60 years of the Journal of Neurochemistry (JNC) - was celebrated with a historical symposium that explored the foundations of neurochemical societies, key international figures in the discipline of neurochemistry, and the pre-eminent role of the JNC. The foundations of neurochemistry were laid in Europe, notably France and Germany, in the late 18th and early 19th centuries. Neurochemists in the United Kingdom made globally relevant contributions before and after the Second World War, and Swedish contributions were especially prominent in the 1950s and 1960s. As neurochemistry is a truly international branch of neuroscience, the important contributions of neurochemists in the Americas and the Asia-Pacific were also recognized, as were the seminal roles of the American, Asia-Pacific, and Japanese Societies of Neurochemistry. Although ISN was only formed in 1967, earlier international meetings in Europe and the Americas reflected the growing recognition of the importance of chemistry and biochemistry for understanding and responding to the pathophysiology of clinical conditions and diseases of the central and peripheral nervous systems. JNC was first published in 1956, but the ISN only assumed complete ownership of the journal under tempestuous circumstances in 1970. The ISN-JNC interface and the sterling work of the JNC Editors has meant that the income generated by the journal has allowed the ISN Council to implement diverse programs for supporting neurochemistry internationally, including sustaining regional neurochemical societies, and supporting neurochemists in the developing world and schools of neurochemistry.
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Affiliation(s)
- Anne I Boullerne
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Paul Foley
- Neuroscience Research Australia, Sydney, New South Wales, Australia
| | | | - Graham A R Johnston
- Discipline of Pharmacology, School of Medical Sciences, University of Sydney, New South Wales, Australia
| | - Philip M Beart
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.,Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia
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9
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Foley PB. Dopamine in psychiatry: a historical perspective. J Neural Transm (Vienna) 2019; 126:473-479. [DOI: 10.1007/s00702-019-01987-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 02/10/2019] [Indexed: 01/11/2023]
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10
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Merighi A. Costorage of High Molecular Weight Neurotransmitters in Large Dense Core Vesicles of Mammalian Neurons. Front Cell Neurosci 2018; 12:272. [PMID: 30186121 PMCID: PMC6110924 DOI: 10.3389/fncel.2018.00272] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/03/2018] [Indexed: 12/19/2022] Open
Abstract
It is today widely accepted that several types of high molecular weight (MW) neurotransmitters produced by neurons are synthesized at the cell body, selectively stored within large dense core vesicles (LDCVs) and anterogradely transported to terminals where they elicit their biological role(s). Among these molecules there are neuropeptides and neurotrophic factors, the main focus of this perspective article. I here first provide a brief resume of the state of art on neuronal secretion, with primary emphasis on the molecular composition and mechanism(s) of filling and release of LDCVs. Then, I discuss the perspectives and future directions of research in the field as regarding the synthesis and storage of multiple high MW transmitters in LDCVs and the possibility that a selective sorting of LDCVs occurs along different neuronal processes and/or their branches. I also consider the ongoing discussion that diverse types of neurons may contain LDCVs with different sets of integral proteins or dial in a different fashion with LDCVs containing the same cargo. In addition, I provide original data on the size of LDCVs in rat dorsal root ganglion neurons and their central terminals in the spinal cord after immunogold labeling for calcitonin gene-related peptide (CGRP), neuropeptide K, substance P, neurokinin A or somatostatin. These data corroborate the idea that, similarly to endocrine cells, LDCVs undergo a process of maturation which involves a homotypic fusion followed by a reduction in size and condensation of cargo. They also give support to the conjecture that release at terminals occurs by cavicapture, a process of partial fusion of the vesicle with the axolemma, accompanied by depletion of cargo and diminution of size.
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Affiliation(s)
- Adalberto Merighi
- Laboratory of Neurobiology, Department of Veterinary Sciences, University of Turin, Turin, Italy
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11
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Early attempts to visualize cortical monoamine nerve terminals. Brain Res 2016; 1645:8-11. [PMID: 26806405 DOI: 10.1016/j.brainres.2016.01.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 11/22/2022]
Abstract
The Falck-Hillarp, formaldehyde fluorescence method for the demonstration of monoamine neurons in a microscope was established in Lund, Sweden and published in 1962. In the same year Hillarp moved to Karolinska Institutet in Stockholm. Two years later Dahlström and Fuxe published the famous supplement in Acta Physiologica Scandinavica, describing the distribution of the dopamine, noradrenaline and serotonin cell groups in the rat brain. This landmark paper also represented an important contribution to an emerging discipline in neuroscience - chemical neuroanatomy. During the following years several modifications of the original method were developed, attempting to solve some shortcomings, one being the reproducible demonstration of noradrenaline nerve terminals in cortical regions. One result was the paper focused on in the present article, which also describes other efforts in the same direction going on in parallel, primarily, in Lund and Stockholm. As a result there was, in the mid 1970s, a fairly complete knowledge of the catecholamine systems in the rat brain. This article is part of a Special Issue entitled SI:50th Anniversary Issue.
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Ugrumov M, Taxi J, Pronina T, Kurina A, Sorokin A, Sapronova A, Calas A. Neurons expressing individual enzymes of dopamine synthesis in the mediobasal hypothalamus of adult rats: functional significance and topographic interrelations. Neuroscience 2014; 277:45-54. [PMID: 24997271 DOI: 10.1016/j.neuroscience.2014.06.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 06/20/2014] [Accepted: 06/24/2014] [Indexed: 11/30/2022]
Abstract
Besides dopaminergic (DA-ergic) neurons having all enzymes of DA synthesis, tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC), "monoenzymatic" neurons expressing only one of them were found in the brain, mostly in the mediobasal hypothalamus (MBH). The aim of this study was to test our hypothesis that DA is synthesized by monoenzymatic neurons, i.e. l-3,4-dihydroxyphenylalanine (l-DOPA), which produced in the monoenzymatic TH neurons is transported in the monoenzymatic AADC neurons for DA synthesis. Incubation of MBH in Krebs-Ringer solution with l-leucine, a competitive inhibitor of l-DOPA uptake, was used to prevent a hypothetical l-DOPA capture into AADC-containing neurons. Incubation of the substantia nigra containing DA-ergic neurons under the same conditions served as the control. According to our data, the l-leucine administration provoked a decrease of DA concentration in MBH and in the incubation medium but not in the substantia nigra and respective incubation medium, showing a decrease of cooperative synthesis of DA in MBH. This conclusion was supported by an observation of higher concentration of l-DOPA in the incubation medium under perfusion of MBH with Krebs-Ringer solution containing tolcapone, an inhibitor of catechol-O-methyltransferase, and l-leucine than under perfusion with the same solution, but without l-leucine. Functional interaction between monoenzymatic TH and AADC neurons was indirectly confirmed by finding in electron microscopy their close relations in MBH. Besides monoenzymatic AADC neurons, any AADC-possessing neurons, catecholaminergic and serotoninergic, apparently, could participate in DA synthesis together with monoenzymatic TH neurons. This idea was confirmed by the observation of close topographic relations between monoenzymatic TH neurons and those containing both enzymes, i.e. DA-ergic, noradrenergic or adrenergic. Thus, monoenzymatic neurons possessing TH or AADC and being in close topographic relations can synthesize DA in cooperation.
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Affiliation(s)
- M Ugrumov
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia.
| | - J Taxi
- Laboratoire de Pathophysiologie des maladies du système nervoux central, UMR5 INSERM 952, IFR 83, Université P. et M. Curie, 7 quai St. Bernard, 75252 Paris Cedex 05, France
| | - T Pronina
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia
| | - A Kurina
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia
| | - A Sorokin
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia; Laboratoire de Pathophysiologie des maladies du système nervoux central, UMR5 INSERM 952, IFR 83, Université P. et M. Curie, 7 quai St. Bernard, 75252 Paris Cedex 05, France
| | - A Sapronova
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia
| | - A Calas
- IINS, UMR CNRS 5297, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux-Cedex, France
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Goyal RK, Chaudhury A. Structure activity relationship of synaptic and junctional neurotransmission. Auton Neurosci 2013; 176:11-31. [PMID: 23535140 PMCID: PMC3677731 DOI: 10.1016/j.autneu.2013.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 12/28/2012] [Accepted: 02/18/2013] [Indexed: 12/18/2022]
Abstract
Chemical neurotransmission may include transmission to local or remote sites. Locally, contact between 'bare' portions of the bulbous nerve terminal termed a varicosity and the effector cell may be in the form of either synapse or non-synaptic contact. Traditionally, all local transmissions between nerves and effector cells are considered synaptic in nature. This is particularly true for communication between neurons. However, communication between nerves and other effectors such as smooth muscles has been described as nonsynaptic or junctional in nature. Nonsynaptic neurotransmission is now also increasingly recognized in the CNS. This review focuses on the relationship between structure and function that orchestrate synaptic and junctional neurotransmissions. A synapse is a specialized focal contact between the presynaptic active zone capable of ultrafast release of soluble transmitters and the postsynaptic density that cluster ionotropic receptors. The presynaptic and the postsynaptic areas are separated by the 'closed' synaptic cavity. The physiological hallmark of the synapse is ultrafast postsynaptic potentials lasting milliseconds. In contrast, junctions are juxtapositions of nerve terminals and the effector cells without clear synaptic specializations and the junctional space is 'open' to the extracellular space. Based on the nature of the transmitters, postjunctional receptors and their separation from the release sites, the junctions can be divided into 'close' and 'wide' junctions. Functionally, the 'close' and the 'wide' junctions can be distinguished by postjunctional potentials lasting ~1s and tens of seconds, respectively. Both synaptic and junctional communications are common between neurons; however, junctional transmission is the rule at many neuro-non-neural effectors.
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Affiliation(s)
- Raj K Goyal
- Center for Swallowing and Motility Disorders, GI Division, VA Boston Healthcare System and Harvard Medical School, Boston, USA.
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Jiménez-Trejo F, León-Galván MÁ, Martínez-Méndez LA, Tapia-Rodríguez M, Mendoza-Rodríguez CA, González-Santoyo I, López-Wilchis R, Vela-Hinojosa C, Baranda-Avila N, Cerbón M. Serotonin in testes of bat Myotis velifer during annual reproductive cycle: expression, localization, and content variations. ACTA ACUST UNITED AC 2013; 319:249-58. [PMID: 23666882 DOI: 10.1002/jez.1789] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/29/2013] [Accepted: 02/09/2013] [Indexed: 11/08/2022]
Abstract
The mechanism of reproduction in mammals is very complex and in some cases is quite particular. For example in some bat species, the male presents a reproductive mechanism characterized by an annual testicular cycle that goes from recrudescence to regression (spermatogenesis to inactivity period, respectively). After recrudescence, the spermatozoa arrive at epididymis and wait to be expelled at the time of ejaculation during the mating period, which occurs some months later. Because serotonin (5-HT) has gained reproductive importance in the last years, the aim of the present study was to analyze the expression of this indolamine and both tryptophan hydroxylase and monoamine oxidase isoform A-enzymes involved in its metabolism-in Myotis velifer testes, a seasonal reproductive bat species that shows temporal asynchrony in its sexual cycle, across the principal periods of their reproductive cycle. By using both Falck-Hillarp histochemistry and immunofluorescence techniques, we found serotonin in vesicles of Leydig cells and probably Sertoli cells too; interestingly, both intracellular localization and concentration was variable across the different stages of the reproductive cycle, being lower during spermatogenesis phase and increasing during the mating phase. These results suggest that 5-HT is present in bat testes and it could play an important role in testicular function during their reproductive cycle.
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Affiliation(s)
- Francisco Jiménez-Trejo
- Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, DF, Mexico
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Ugrumov MV. Brain neurons partly expressing dopaminergic phenotype: location, development, functional significance, and regulation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 68:37-91. [PMID: 24054140 DOI: 10.1016/b978-0-12-411512-5.00004-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In addition to catecholaminergic neurons possessing all the enzymes of catecholamine synthesis and the specific membrane transporters, neurons partly expressing the catecholaminergic phenotype have been found a quarter of a century ago. Most of them express individual enzymes of dopamine (DA) synthesis, tyrosine hydroxylase (TH), or aromatic l-amino acid decarboxylase (AADC), lacking the DA membrane transporter and the vesicular monoamine transporter, type 2. These so-called monoenzymatic neurons are widely distributed throughout the brain in ontogenesis and adulthood being in some brain regions even more numerous than dopaminergic (DA-ergic) neurons. Individual enzymes of DA synthesis are expressed in these neurons continuously or transiently in norm and pathology. It has been proven that monoenzymatic TH neurons and AADC neurons are capable of producing DA in cooperation. It means that l-3,4-dihydroxyphenylalanine (l-DOPA) synthesized from l-tyrosine in monoenzymatic TH neurons is transported to monoenzymatic AADC neurons for DA synthesis. Such cooperative synthesis of DA is considered as a compensatory reaction under a failure of DA-ergic neurons, for example, in neurodegenerative diseases like hyperprolactinemia and Parkinson's disease. Moreover, l-DOPA, produced in monoenzymatic TH neurons, is assumed to play a role of a neurotransmitter or neuromodulator affecting the target neurons via catecholamine receptors. Thus, numerous widespread neurons expressing individual complementary enzymes of DA synthesis serve to produce DA in cooperation that is a compensatory reaction at failure of DA-ergic neurons.
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Affiliation(s)
- Michael V Ugrumov
- Institute of Developmental Biology and Centre for Brain Research, Russian Academy of Sciences, Moscow, Russia; Institute of Normal Physiology RAMS, Moscow, Russia.
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Graeff FG. New perspective on the pathophysiology of panic: merging serotonin and opioids in the periaqueductal gray. Braz J Med Biol Res 2012; 45:366-75. [PMID: 22437485 PMCID: PMC3854168 DOI: 10.1590/s0100-879x2012007500036] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 03/08/2012] [Indexed: 12/15/2022] Open
Abstract
Panic disorder patients are vulnerable to recurrent panic attacks. Two neurochemical hypotheses have been proposed to explain this susceptibility. The first assumes that panic patients have deficient serotonergic inhibition of neurons localized in the dorsal periaqueductal gray matter of the midbrain that organize defensive reactions to cope with proximal threats and of sympathomotor control areas of the rostral ventrolateral medulla that generate most of the neurovegetative symptoms of the panic attack. The second suggests that endogenous opioids buffer normal subjects from the behavioral and physiological manifestations of the panic attack, and their deficit brings about heightened suffocation sensitivity and separation anxiety in panic patients, making them more vulnerable to panic attacks. Experimental results obtained in rats performing one-way escape in the elevated T-maze, an animal model of panic, indicate that the inhibitory action of serotonin on defense is connected with activation of endogenous opioids in the periaqueductal gray. This allows reconciliation of the serotonergic and opioidergic hypotheses of panic pathophysiology, the periaqueductal gray being the fulcrum of serotonin-opioid interaction.
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Affiliation(s)
- F G Graeff
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brasil.
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Merighi A, Salio C, Ferrini F, Lossi L. Neuromodulatory function of neuropeptides in the normal CNS. J Chem Neuroanat 2011; 42:276-87. [PMID: 21385606 DOI: 10.1016/j.jchemneu.2011.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 02/08/2011] [Accepted: 02/09/2011] [Indexed: 01/15/2023]
Abstract
Neuropeptides are small protein molecules produced and released by discrete cell populations of the central and peripheral nervous systems through the regulated secretory pathway and acting on neural substrates. Inside the nerve cells, neuropeptides are selectively stored within large granular vesicles (LGVs), and commonly coexist in neurons with low-molecular-weight neurotransmitters (acetylcholine, amino acids, and catecholamines). Storage in LGVs is responsible for a relatively slow response to secretion that requires enhanced or repeated stimulation. Coexistence (i.e. the concurrent presence of a neuropeptide with other messenger molecules in individual neurons), and co-storage (i.e. the localization of two or more neuropeptides within individual LGVs in neurons) give rise to a complicated series of pre- and post-synaptic functional interactions with low-molecular-weight neurotransmitters. The typically slow response and action of neuropeptides as compared to fast-neurotransmitters such as excitatory/inhibitory amino acids and catecholamines is also due to the type of receptors that trigger neuropeptide actions onto target cells. Almost all neuropeptides act on G-protein coupled receptors that, upon ligand binding, activate an intracellular cascade of molecular enzymatic events, eventually leading to cellular responses. The latter occur in a time span (seconds or more) considerably longer (milliseconds) than that of low-molecular-weight fast-neurotransmitters, directly operating through ion channel receptors. As reviewed here, combined immunocytochemical visualization of neuropeptides and their receptors at the ultrastructural level and electrophysiological studies, have been fundamental to better unravel the role of neuropeptides in neuron-to-neuron communication.
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Affiliation(s)
- Adalberto Merighi
- University of Turin, Department of Veterinary Morphophysiology, Via Leonardo da Vinci 44, 10095 Grugliasco, Torino, Italy.
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Eberwine J, Bartfai T. Single cell transcriptomics of hypothalamic warm sensitive neurons that control core body temperature and fever response Signaling asymmetry and an extension of chemical neuroanatomy. Pharmacol Ther 2010; 129:241-59. [PMID: 20970451 DOI: 10.1016/j.pharmthera.2010.09.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 09/30/2010] [Indexed: 12/11/2022]
Abstract
We report on an 'unbiased' molecular characterization of individual, adult neurons, active in a central, anterior hypothalamic neuronal circuit, by establishing cDNA libraries from each individual, electrophysiologically identified warm sensitive neuron (WSN). The cDNA libraries were analyzed by Affymetrix microarray. The presence and frequency of cDNAs were confirmed and enhanced with Illumina sequencing of each single cell cDNA library. cDNAs encoding the GABA biosynthetic enzyme Gad1 and of adrenomedullin, galanin, prodynorphin, somatostatin, and tachykinin were found in the WSNs. The functional cellular and in vivo studies on dozens of the more than 500 neurotransmitters, hormone receptors and ion channels, whose cDNA was identified and sequence confirmed, suggest little or no discrepancy between the transcriptional and functional data in WSNs; whenever agonists were available for a receptor whose cDNA was identified, a functional response was found. Sequencing single neuron libraries permitted identification of rarely expressed receptors like the insulin receptor, adiponectin receptor 2 and of receptor heterodimers; information that is lost when pooling cells leads to dilution of signals and mixing signals. Despite the common electrophysiological phenotype and uniform Gad1 expression, WSN transcriptomes show heterogeneity, suggesting strong epigenetic influence on the transcriptome. Our study suggests that it is well-worth interrogating the cDNA libraries of single neurons by sequencing and chipping.
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Affiliation(s)
- James Eberwine
- Department of Pharmacology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
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