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Roman E, Weininger J, Lim B, Roman M, Barry D, Tierney P, O'Hanlon E, Levins K, O'Keane V, Roddy D. Untangling the dorsal diencephalic conduction system: a review of structure and function of the stria medullaris, habenula and fasciculus retroflexus. Brain Struct Funct 2020; 225:1437-1458. [PMID: 32367265 DOI: 10.1007/s00429-020-02069-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 04/11/2020] [Indexed: 12/23/2022]
Abstract
The often-overlooked dorsal diencephalic conduction system (DDCS) is a highly conserved pathway linking the basal forebrain and the monoaminergic brainstem. It consists of three key structures; the stria medullaris, the habenula and the fasciculus retroflexus. The first component of the DDCS, the stria medullaris, is a discrete bilateral tract composed of fibers from the basal forebrain that terminate in the triangular eminence of the stalk of the pineal gland, known as the habenula. The habenula acts as a relay hub where incoming signals from the stria medullaris are processed and subsequently relayed to the midbrain and hindbrain monoaminergic nuclei through the fasciculus retroflexus. As a result of its wide-ranging connections, the DDCS has recently been implicated in a wide range of behaviors related to reward processing, aversion and motivation. As such, an understanding of the structure and connections of the DDCS may help illuminate the pathophysiology of neuropsychiatric disorders such as depression, addiction and pain. This is the first review of all three components of the DDCS, the stria medullaris, the habenula and the fasciculus retroflexus, with particular focus on their anatomy, function and development.
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Affiliation(s)
- Elena Roman
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.,Department of Psychiatry, Education and Research Centre , Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Joshua Weininger
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Basil Lim
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.,Department of Game Design, Technological University Dublin, Dublin 2, Ireland
| | - Marin Roman
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Denis Barry
- Anatomy Department, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Paul Tierney
- Anatomy Department, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Erik O'Hanlon
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.,Department of Psychiatry, Education and Research Centre , Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Kirk Levins
- Department of Anaesthetics, Intensive Care and Pain Medicine, St. Vincent's University Hospital, Dublin 4, Ireland
| | - Veronica O'Keane
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Darren Roddy
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.
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Cao Q, Wang Y, Chen B, Ma F, Hao L, Li G, Ouyang C, Li L. Visualization and Identification of Neurotransmitters in Crustacean Brain via Multifaceted Mass Spectrometric Approaches. ACS Chem Neurosci 2019; 10:1222-1229. [PMID: 30721026 PMCID: PMC6436947 DOI: 10.1021/acschemneuro.8b00730] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has emerged as a label-free analytical tool for fast biomolecule profiling on tissue sections. Among various functional molecules, mapping neurotransmitters and related metabolites is of tremendous significance, as these compounds are critical to signaling in the central nervous system. Here, we demonstrated the use of both derivatization and reaction-free approaches that greatly reduced signal complexity and thus enabled complementary signaling molecule visualization on crab brain sections via MALDI-LTQ-Orbitrap XL platform. Pyrylium salt served as a primary amine derivatization reagent and produced prominent signal enhancement of multiple neurotransmitters, including dopamine, serotonin, γ-aminobutyric acid, and histamine that were not detected in underivatized tissues. Molecules with other functional groups, such as acetylcholine and phosphocholine, were directly imaged after matrix application. The identities of discovered neurotransmitters were verified by standards using LC-MS/MS. This study broadens our understanding of metabolic signaling in the crustacean nervous system and highlights potential of multifaceted MS techniques for unambiguous neurotransmitter characterization.
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Affiliation(s)
- Qinjingwen Cao
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Yijia Wang
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Bingming Chen
- School of Pharmacy, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Fengfei Ma
- School of Pharmacy, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Ling Hao
- School of Pharmacy, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Gongyu Li
- School of Pharmacy, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Chuanzi Ouyang
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- School of Pharmacy, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
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Lénárd L, László K, Kertes E, Ollmann T, Péczely L, Kovács A, Kállai V, Zagorácz O, Gálosi R, Karádi Z. Substance P and neurotensin in the limbic system: Their roles in reinforcement and memory consolidation. Neurosci Biobehav Rev 2018; 85:1-20. [DOI: 10.1016/j.neubiorev.2017.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/24/2017] [Accepted: 09/02/2017] [Indexed: 12/18/2022]
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Khan AM, Grant AH, Martinez A, Burns GAPC, Thatcher BS, Anekonda VT, Thompson BW, Roberts ZS, Moralejo DH, Blevins JE. Mapping Molecular Datasets Back to the Brain Regions They are Extracted from: Remembering the Native Countries of Hypothalamic Expatriates and Refugees. ADVANCES IN NEUROBIOLOGY 2018; 21:101-193. [PMID: 30334222 PMCID: PMC6310046 DOI: 10.1007/978-3-319-94593-4_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This article focuses on approaches to link transcriptomic, proteomic, and peptidomic datasets mined from brain tissue to the original locations within the brain that they are derived from using digital atlas mapping techniques. We use, as an example, the transcriptomic, proteomic and peptidomic analyses conducted in the mammalian hypothalamus. Following a brief historical overview, we highlight studies that have mined biochemical and molecular information from the hypothalamus and then lay out a strategy for how these data can be linked spatially to the mapped locations in a canonical brain atlas where the data come from, thereby allowing researchers to integrate these data with other datasets across multiple scales. A key methodology that enables atlas-based mapping of extracted datasets-laser-capture microdissection-is discussed in detail, with a view of how this technology is a bridge between systems biology and systems neuroscience.
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Affiliation(s)
- Arshad M Khan
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, TX, USA.
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA.
- Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX, USA.
| | - Alice H Grant
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, TX, USA
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
- Graduate Program in Pathobiology, University of Texas at El Paso, El Paso, TX, USA
| | - Anais Martinez
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, TX, USA
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
- Graduate Program in Pathobiology, University of Texas at El Paso, El Paso, TX, USA
| | - Gully A P C Burns
- Information Sciences Institute, Viterbi School of Engineering, University of Southern California, Marina del Rey, CA, USA
| | - Brendan S Thatcher
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, USA
| | - Vishwanath T Anekonda
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, USA
| | - Benjamin W Thompson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, USA
| | - Zachary S Roberts
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, USA
| | - Daniel H Moralejo
- Division of Neonatology, Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
| | - James E Blevins
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, USA
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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Agoston DV. Great insight created by tiny holes; celebrating 40 years of brain micropunch technique. Front Neuroanat 2014; 8:61. [PMID: 25071466 PMCID: PMC4092355 DOI: 10.3389/fnana.2014.00061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 06/13/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Denes V Agoston
- Anatomy, Physiology and Genetics, Uniformed Services University Bethesda, MD, USA ; Experimental Traumatology, Department of Neuroscience, Karolinska Institute Stockholm, Sweden
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Khan AM. Controlling feeding behavior by chemical or gene-directed targeting in the brain: what's so spatial about our methods? Front Neurosci 2013; 7:182. [PMID: 24385950 PMCID: PMC3866545 DOI: 10.3389/fnins.2013.00182] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 09/20/2013] [Indexed: 12/26/2022] Open
Abstract
Intracranial chemical injection (ICI) methods have been used to identify the locations in the brain where feeding behavior can be controlled acutely. Scientists conducting ICI studies often document their injection site locations, thereby leaving kernels of valuable location data for others to use to further characterize feeding control circuits. Unfortunately, this rich dataset has not yet been formally contextualized with other published neuroanatomical data. In particular, axonal tracing studies have delineated several neural circuits originating in the same areas where ICI injection feeding-control sites have been documented, but it remains unclear whether these circuits participate in feeding control. Comparing injection sites with other types of location data would require careful anatomical registration between the datasets. Here, a conceptual framework is presented for how such anatomical registration efforts can be performed. For example, by using a simple atlas alignment tool, a hypothalamic locus sensitive to the orexigenic effects of neuropeptide Y (NPY) can be aligned accurately with the locations of neurons labeled by anterograde tracers or those known to express NPY receptors or feeding-related peptides. This approach can also be applied to those intracranial "gene-directed" injection (IGI) methods (e.g., site-specific recombinase methods, RNA expression or interference, optogenetics, and pharmacosynthetics) that involve viral injections to targeted neuronal populations. Spatial alignment efforts can be accelerated if location data from ICI/IGI methods are mapped to stereotaxic brain atlases to allow powerful neuroinformatics tools to overlay different types of data in the same reference space. Atlas-based mapping will be critical for community-based sharing of location data for feeding control circuits, and will accelerate our understanding of structure-function relationships in the brain for mammalian models of obesity and metabolic disorders.
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Affiliation(s)
- Arshad M. Khan
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El PasoEl Paso, TX, USA
- Neurobiology Section, Department of Biological Sciences, University of Southern CaliforniaLos Angeles, CA, USA
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Mesulam MM. Cholinergic circuitry of the human nucleus basalis and its fate in Alzheimer's disease. J Comp Neurol 2013; 521:4124-44. [PMID: 23852922 PMCID: PMC4175400 DOI: 10.1002/cne.23415] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/11/2013] [Accepted: 06/28/2013] [Indexed: 01/15/2023]
Abstract
The nucleus basalis is located at the confluence of the limbic and reticular activating systems. It receives dopaminergic input from the ventral tegmental area/substantia nigra, serotonergic input from the raphe nuclei, and noradrenergic input from the nucleus locus coeruleus. Its cholinergic contingent, known as Ch4, provides the principal source of acetylcholine for the cerebral cortex and amygdala. More than half of presynaptic varicosities along its cholinergic axons make traditional synaptic contacts with cortical neurons. Limbic and paralimbic cortices of the brain receive the heaviest cholinergic input from Ch4 and are also the principal sources of reciprocal cortical projections back to the nucleus basalis. This limbic affiliation explains the role of the nucleus basalis in modulating the impact and memorability of incoming sensory information. The anatomical continuity of the nucleus basalis with other basomedial limbic structures may underlie its early and high vulnerability to the tauopathy and neurofibrillary degeneration of Alzheimer's disease. The tauopathy in Ch4 eventually leads to the degeneration of the cholinergic axons that it sends to the cerebral cortex. The early involvement of Ch4 has a magnifying effect on Alzheimer's pathology, because neurofibrillary degeneration in a small number of neurons can perturb neurotransmission in all cortical areas. Although the exact contribution of the Ch4 lesion to the cognitive changes of Alzheimer's disease remains poorly understood, the cholinergic circuitry of the nucleus basalis is emerging as one of the most strategically positioned and behaviorally consequential modulatory systems of the human cerebral cortex. J. Comp. Neurol. 521:4124-4144, 2013. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- M.-Marsel Mesulam
- Cognitive Neurology and Alzheimer's Disease Center, Northwestern University Medical School, Chicago, Illinois 60611
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Stereotaxic mapping of brainstem areas critical for the expression of the rodent’s preference for the dark. ACTA ACUST UNITED AC 2013. [DOI: 10.3758/bf03335202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ye H, Wang J, Greer T, Strupat K, Li L. Visualizing neurotransmitters and metabolites in the central nervous system by high resolution and high accuracy mass spectrometric imaging. ACS Chem Neurosci 2013; 4:1049-56. [PMID: 23607816 DOI: 10.1021/cn400065k] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The spatial localization and molecular distribution of metabolites and neurotransmitters within biological organisms is of tremendous interest to neuroscientists. In comparison to conventional imaging techniques such as immunohistochemistry, matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging (MSI) has demonstrated its unique advantage by directly localizing the distribution of a wide range of biomolecules simultaneously from a tissue specimen. Although MALDI-MSI of metabolites and neurotransmitters is hindered by numerous matrix-derived peaks, high-resolution and high-accuracy mass spectrometers (HRMS) allow differentiation of endogenous analytes from matrix peaks, unambiguously obtaining biomolecular distributions. In this study, we present MSI of metabolites and neurotransmitters in rodent and crustacean central nervous systems acquired on HRMS. Results were compared with those obtained from a medium-resolution mass spectrometer (MRMS), tandem time-of-flight instrument, to demonstrate the power and unique advantages of HRMSI and reveal how this new tool would benefit molecular imaging applications in neuroscience.
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Conductier G, Nahon JL, Guyon A. Dopamine depresses melanin concentrating hormone neuronal activity through multiple effects on α2-noradrenergic, D1 and D2-like dopaminergic receptors. Neuroscience 2011; 178:89-100. [PMID: 21262322 DOI: 10.1016/j.neuroscience.2011.01.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/27/2010] [Accepted: 01/17/2011] [Indexed: 10/18/2022]
Abstract
Two neuronal populations of the lateral hypothalamus that, respectively, produce melanin-concentrating hormone (MCH) and orexin peptides are crucially involved in control of metabolism, feeding and related goal-oriented behaviors. In contrast to orexin neurons, mainly involved in short-term regulation of feeding, MCH neurons participate in long-term control of energy storage and body weight. Beyond its effect on feeding, MCH has also been shown to be involved in regulation of seeking behavior and addiction through modulation of dopamine (DA) metabolism. This regulation is essential for reinforcement-associated behaviors. Moreover, drugs of abuse, which increase extracellular DA levels, are known to decrease food intake. Consistent with this observation, DA has been shown to modulate orexin neurons of the lateral hypothalamus. However, no study is available concerning the effects of DA on MCH neurons. Whole-cell patch-clamp recordings were done in hypothalamic mouse brain slices. MCH neurons were identified by Tau-Cyan-GFP labeling using a transgenic mouse model (MCH-GFP). First, we show that DA (10-200 μM) induces an outward current in MCH neurons. However, this current is not due to activation of DA receptors, but mediated through activation of α2-noradrenergic receptors and subsequent opening of G-protein activated inward rectifier K+ (GIRK) channels. Current-clamp experiments revealed that this GIRK-activation leads to hyperpolarization, thus decreasing excitability of MCH neurons. Furthermore, we confirm that MCH neurons receive mainly GABAergic inputs rather than glutamatergic ones. We show that DA modulates these inputs in a complex manner: at low concentrations, DA activates D1-like receptors, promoting presynaptic activity, whereas, at higher concentrations (100 μM), D2-like receptor activation inhibits presynaptic activity. Overall, DA should lead to a decrease in MCH neuron excitability, likely resulting in down-regulation of MCH release and feeding behavior.
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Affiliation(s)
- G Conductier
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR6097, Centre National de la Recherche Scientifique (CNRS), 660 route des Lucioles, Valbonne, France
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Shaw VE, Keay KA, Ashkan K, Benabid AL, Mitrofanis J. Dopaminergic cells in the periaqueductal grey matter of MPTP-treated monkeys and mice; patterns of survival and effect of deep brain stimulation and lesion of the subthalamic nucleus. Parkinsonism Relat Disord 2010; 16:338-44. [PMID: 20227323 DOI: 10.1016/j.parkreldis.2010.02.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/15/2010] [Accepted: 02/16/2010] [Indexed: 11/28/2022]
Abstract
In this anatomical study, we have examined the number of tyrosine hydroxylase (TH) cells in the periaqueductal grey matter (PAG) of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys and mice; further, we explored whether kainic acid lesion or deep brain stimulation (DBS) of the subthalamic nucleus (STN) in MPTP-treated monkeys has any impact on the number of TH(+) cells in the PAG. For monkeys, there were four groups: Normal, MPTP, STN-lesioned (+MPTP) and STN-DBS (+MPTP). For mice, BALB/c albino mice were divided into three groups, Saline, MPTP_50 (50 mg/kg), MPTP_100 (100 mg/kg). Animals were perfused transcardially with aldehyde fixative 6-12 days after their last MPTP injection. Brains were processed for immunochemistry and the number of cells was estimated using the optical fractionator method. Our results revealed significant reductions (25-30%) in TH(+) cell number in the PAG of MPTP-treated monkeys and mice compared to controls. These reductions were not as substantial as those recorded in the SNc in the same animals (40-60%). Further, in monkeys, there were significantly more TH(+) cells in the PAG of STN-lesioned and STN-DBS groups compared to the MPTP group. In fact, the number of TH(+) cells in the STN alteration cases were similar to the Normal group. In summary, our results indicated that MPTP is toxic to TH(+) cells in the PAG of monkeys and mice and that in monkeys, lesion or DBS of the STN offers neuroprotection against this toxicity.
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Affiliation(s)
- Victoria E Shaw
- Discipline of Anatomy & Histology F13, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
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EEG desynchronization is associated with cellular events that are prerequisites for active behavioral states. Behav Brain Sci 2010. [DOI: 10.1017/s0140525x00010037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
AbstractIt is traditionally believed that cerebral activation (the presence of low voltage fast electrical activity in the neocortex and rhythmical slow activity in the hippocampus) is correlated with arousal, while deactivation (the presence of large amplitude irregular slow waves or spindles in both the neocortex and the hippocampus) is correlated with sleep or coma. However, since there are many exceptions, these generalizations have only limited validity. Activated patterns occur in normal sleep (active or paradoxical sleep) and during states of anesthesia and coma. Deactivated patterns occur, at times, during normal waking, or during behavior in awake animals treated with atropinic drugs. Also, the fact that patterns characteristic of sleep, arousal, and waking behavior continue in decorticate animals indicates that reticulo-cortical mechanisms are not essential for these aspects of behavior.These puzzles have been largely resolved by recent research indicating that there are two different kinds of input from the reticular activating system to the hippocampus and neocortex. One input is probably cholinergic; it may play a role in stimulus control of behavior. The second input is noncholinergic and appears to be related to motor activity; movement-related input to the neocortex may be dependent on a trace amine.Reticulo-cortical systems are not related to arousal in the traditional sense, but may play a role in the control of adaptive behavior by influencing the activity of the cerebral cortex, which in turn exerts control over subcortical circuits that co-ordinate muscle activity to produce behavior.
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Shaw VE, Spana S, Ashkan K, Benabid AL, Stone J, Baker GE, Mitrofanis J. Neuroprotection of midbrain dopaminergic cells in MPTP-treated mice after near-infrared light treatment. J Comp Neurol 2010; 518:25-40. [PMID: 19882716 DOI: 10.1002/cne.22207] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study explores whether near-infrared (NIr) light treatment neuroprotects dopaminergic cells in the substantia nigra pars compacta (SNc) and the zona incerta-hypothalamus (ZI-Hyp) from degeneration in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice. BALB/c albino mice were divided into four groups: 1) Saline, 2) Saline-NIr, 3) MPTP, 4) MPTP-NIr. The injections were intraperitoneal and they were followed immediately by NIr light treatment (or not). Two doses of MPTP, mild (50 mg/kg) and strong (100 mg/kg), were used. Mice were perfused transcardially with aldehyde fixative 6 days after their MPTP treatment. Brains were processed for tyrosine hydroxylase (TH) immunochemistry. The number of TH(+) cells was estimated using the optical fractionator method. Our major finding was that in the SNc there were significantly more dopaminergic cells in the MPTP-NIr compared to the MPTP group (35%-45%). By contrast, in the ZI-Hyp there was no significant difference in the numbers of cells in these two groups. In addition, our results indicated that survival in the two regions after MPTP insult was dose-dependent. In the stronger MPTP regime, the magnitude of loss was similar in the two regions ( approximately 60%), while in the milder regime cell loss was greater in the SNc (45%) than ZI-Hyp ( approximately 30%). In summary, our results indicate that NIr light treatment offers neuroprotection against MPTP toxicity for dopaminergic cells in the SNc, but not in the ZI-Hyp.
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Affiliation(s)
- Victoria E Shaw
- Discipline of Anatomy & Histology F13, University of Sydney, Australia
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Parent M, Descarries L. Acetylcholine innervation of the adult rat thalamus: Distribution and ultrastructural features in dorsolateral geniculate, parafascicular, and reticular thalamic nuclei. J Comp Neurol 2008; 511:678-91. [DOI: 10.1002/cne.21868] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kramer PR, Guan G, Wellman PJ, Bellinger LL. Nicotine's attenuation of body weight involves the perifornical hypothalamus. Life Sci 2007; 81:500-8. [PMID: 17655879 PMCID: PMC2725327 DOI: 10.1016/j.lfs.2007.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 05/31/2007] [Accepted: 06/14/2007] [Indexed: 11/28/2022]
Abstract
Previously we showed that intermittent administration of nicotine (NIC) in the dark phase decreased food intake and body weight and this could be blocked when the NIC receptor antagonist mecamylamine was infused into the fourth ventricle. Catecholaminergic neurons adjacent to the fourth ventricle contain NIC receptors and directly innervate the perifornical hypothalamus (PFH) which has been shown to be involved in regulation of feeding. This study explored whether NIC regulates feeding behavior by modulating catecholaminergic input to the PFH. Epinephrine and norepinephrine neuronal input was ablated within the PFH by infusion of 6-hydroxydopamine hydrobromide (6-OHDA), while bupropion was infused to protect dopaminergic neurons. After recovery of body weights to pre-surgery levels, food intake, meal size, meal number and body weight were measured after intermittent NIC injections. The results showed the PFH lesioned animals did not exhibit the typical prolonged drop in food intake, meal size and body weight normally associated with NIC administration. High performance liquid chromatography analyses demonstrated that compared to control rats, 6-OHDA administration significantly reduced PFH norepinephrine and epinephrine levels, but not dopamine levels. These results are consistent with NIC reducing food intake in part by acting through catecholaminergic neurons within or extending through the PFH.
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Affiliation(s)
- Phillip R Kramer
- Department of Biomedical Sciences, Baylor College of Dentistry, Texas A&M University System Health Science Center, 3302 Gaston Ave. Dallas, TX 75246, USA.
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Ku YH, Wang M, Li YH, Sun ZJ, Guo T, Wu JS. Repetition rates of specific interval patterns in single spike train reflect excitation level of specific receptor types, shown by high-speed favored-pattern detection method. Brain Res 2006; 1113:110-28. [PMID: 16934232 DOI: 10.1016/j.brainres.2006.06.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2006] [Revised: 06/28/2006] [Accepted: 06/30/2006] [Indexed: 11/16/2022]
Abstract
UNLABELLED Interval patterns in single spike train, e.g. "favored patterns (FPs, the FP is a sequence of successive intervals of action potentials that occur more often than what is reasonably expected at random.)", may represent neural codes containing information. The present study developed a "high-speed FP-detection method" which could qualitatively and quantitatively analyze FPs. By using this method, single spike trains of nucleus paraventricularis (NPV) and rostral ventrolateral medulla (RVL) having different firing patterns, being involved in regulation of arterial pressure, and controlled by different transmitters, were chosen for analysis. RESULTS (1) Corticotropin releasing factor, substance P and agonists of alpha-, beta- and M-receptor microinjected into these brain areas, respectively, induced dominant change of specific FP. Repetition rates of specific FPs reflect excitation level of specific receptor types. It shows that chemical codes (different transmitters with their receptor types or subtypes) are transformed into electrical codes (different FPs). (2) When alpha-, beta- and M-receptors of RVL neurons were activated simultaneously by intrinsic excitatory transmitters released due to activation of input pathway, only repetition rate of the specific FP that represented the predominant activity of the receptor type (alpha-adrenergic receptor) markedly increased. The activities of other receptor types (beta- and M-receptors) were masked. (3) Intrinsic inhibitory transmitters (GABA, beta-endorphin) in the RVL all decreased specific FP repetition rate of dominant receptor type. These results may provide a new way to further explore how information in the CNS is conveyed and processed.
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Affiliation(s)
- Yun-Hui Ku
- Department of Physiology, Peking University Health Science Center, Beijing 100083, PR China.
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26
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Jacobowitz DM. Differential effects of polyunsaturated fatty acids on membrane capacitance and exocytosis in rat pheochromocytoma-12 cells. Neurochem Res 2006; 31:125-6. [PMID: 16673172 DOI: 10.1007/s11064-005-9002-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
The fusion of synaptic vesicles with the plasma membrane during exocytosis can be recorded by membrane capacitance measurements under voltage-clamp conditions. These measurements enable high time-resolution quantitation of exocytosis. The present study was carried out using the above technique to elucidate the effects of various polyunsaturated fatty acids on exocytosis in a neuroendocrine cell, the rat pheochromocytoma-12 (PC12) cell. External application of eicosapentaenoic acid and arachidonic acid resulted in an increase in capacitance of PC12 cells, indicating fusion of secretory vesicles with cell membranes and exocytosis. In contrast, docosahexaenoic acid, linoleic acid, oleic acid, and vehicle control had no significant effect on capacitance. The above findings show differential effects of polyunsaturated fatty acids on exocytosis in PC12 cells. It is postulated that besides arachidonic acid, eicosapentaenoic acid could also play an important role in exocytosis and neurotransmitter release, in neurons and hormone-secreting cells.
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Affiliation(s)
- David M Jacobowitz
- Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, MD 20892, USA
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27
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Fernández de Sevilla D, Rodrigo-Angulo M, Nuñez A, Buño W. Cholinergic modulation of synaptic transmission and postsynaptic excitability in the rat gracilis dorsal column nucleus. J Neurosci 2006; 26:4015-25. [PMID: 16611818 PMCID: PMC6673877 DOI: 10.1523/jneurosci.5489-05.2006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Somatosensory information, conveyed through the gracilis nucleus (GN), is regulated by descending corticofugal (CF) glutamatergic fibers. In addition, the GN receives cholinergic inputs with still unclear source and functional significance. Using both the in vitro slice and intracellular recording with sharp and patch electrodes and in vivo extracellular single-unit recordings, we analyzed the effects of activation of cholinergic receptors on synaptic, intrinsic, and functional properties of rat GN neurons. The cholinergic agonist carbamilcholine-chloride [carbachol (CCh); 1-10 microM] in vitro (1) induced presynaptic inhibition of EPSPs evoked by both dorsal column and CF stimulation, (2) increased postsynaptic excitability, and (3) amplified the spike output of GN neurons. The inhibition by atropine (1 microM) and pirenzepine (10 microM) of all presynaptic and postsynaptic effects of CCh suggests actions through muscarinic M1 receptors. The above effects were insensitive to nicotinic antagonists. We searched the anatomical origin of the cholinergic projection to the GN throughout the hindbrain and forebrain, and we found that the cholinergic fibers originated mainly in the pontine reticular nucleus (PRN). Electrical stimulation of the PRN amplified sensory responses in the GN in vivo, an effect prevented by topical application of atropine. Our results demonstrate for the first time that cholinergic agonists induce both presynaptic and postsynaptic effects on GN neurons and suggest an important regulatory action of inputs from cholinergic neuronal groups in the pontine reticular formation in the functional control of somatosensory information flow in the GN.
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28
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The Birth of Neurochemical Maps. Neurochem Res 2006. [DOI: 10.1007/pl00022049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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29
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King BM. The rise, fall, and resurrection of the ventromedial hypothalamus in the regulation of feeding behavior and body weight. Physiol Behav 2006; 87:221-44. [PMID: 16412483 DOI: 10.1016/j.physbeh.2005.10.007] [Citation(s) in RCA: 335] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
Early researchers found that lesions of the ventromedial hypothalamus (VMH) resulted in hyperphagia and obesity in a variety of species including humans, which led them to designate the VMH as the brain's "satiety center." Many researchers later dismissed a role for the VMH in feeding behavior when Gold claimed that lesions restricted to the VMH did not result in overeating and that obesity was observed only with lesions or knife cuts that extended beyond the borders of the VMH and damaged or severed the ventral noradrenergic bundle (VNAB) or paraventricular nucleus (PVN). However, anatomical studies done both before and after Gold's study did not replicate his results with lesions, and in nearly every published direct comparison of VMH lesions vs. PVN or VNAB lesions, the group with VMH lesions ate substantially more food and gained twice as much weight. Several other important differences have also been found between VMH and both PVN and VNAB lesion-induced obesity. Concerns regarding (a) motivation to work for food and (b) the effects of nonirritative lesions have also been addressed and answered in many studies. Lesion studies with weanling rats and adult pair-tube-fed rats, as well as recent studies of knockout mice deficient in the orphan nuclear receptor steroidogenic factor 1, indicate that VMH lesion-induced obesity is in large part a metabolic obesity (due to autonomic nervous system disorders) independent of hyperphagia. However, there is ample evidence that the VMH also plays a primary role in feeding behavior. Neuroimaging studies in humans have shown a marked increase in activity in the area of the VMH during feeding. The VMH has a large population of glucoresponsive neurons that dynamically respond to blood glucose levels and numerous histamine, dopamine, serotonin, and GABA neurons that respond to feeding-related stimuli. Recent studies have implicated melanocortins in the VMH regulation of feeding behavior: food intake decreases when arcuate nucleus pro-opiomelanocortin (POMC) neurons activate VMH brain-derived neurotrophic factor (BDNF) neurons. Moderate hyperphagia and obesity have also been observed in female rats with damage to the efferent projections from the posterodorsal amygdala to the VMH. Hypothalamic obesity can result from damage to either the POMC or BDNF neurons. The concept of hypothalamic feeding and satiety centers is outdated and unnecessary, and progress in understanding hypothalamic mechanisms of feeding behavior will be achieved only by appreciating the different types of neural and blood-borne information received by the various nuclei, and then attempting to determine how this information is integrated to obtain a balance between energy intake and energy output.
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Affiliation(s)
- Bruce M King
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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30
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Chou TC, Rotman SR, Saper CB. Lateral hypothalamic acetylcholinesterase-immunoreactive neurons co-express either orexin or melanin concentrating hormone. Neurosci Lett 2005; 370:123-6. [PMID: 15488307 DOI: 10.1016/j.neulet.2004.08.070] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 08/04/2004] [Accepted: 08/04/2004] [Indexed: 11/24/2022]
Abstract
The lateral hypothalamic area (LHA) contains a large population of neurons that express the enzyme acetylcholinesterase (AChE), but are not themselves cholinergic. Some of these neurons have been shown to contain melanin-concentrating hormone (MCH), a neuropeptide implicated in regulating feeding, but the identities of the remaining neurons are unknown. We now report that nearly all AChE-immunoreactive neurons in the LHA express immunoreactivity for either MCH or for orexin, a peptide implicated in regulating wakefulness. Furthermore, most orexin neurons and MCH neurons appear to contain AChE. AChE immunoreactivity appears to be a key feature of nearly all of the diffusely-projecting cortical systems.
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Affiliation(s)
- Thomas C Chou
- Department of Neurology and Program in Neuroscience, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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31
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Jacobowitz DM. Professional biographical sketch. Neurotox Res 2004; 6:i-xiv. [PMID: 15614981 DOI: 10.1007/bf03033445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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32
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Guan G, Kramer SF, Bellinger LL, Wellman PJ, Kramer PR. Intermittent nicotine administration modulates food intake in rats by acting on nicotine receptors localized to the brainstem. Life Sci 2004; 74:2725-37. [PMID: 15043987 DOI: 10.1016/j.lfs.2003.10.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2003] [Accepted: 10/08/2003] [Indexed: 11/15/2022]
Abstract
Previous studies have shown nicotine (NIC) administration leads to decreased food intake, while other investigations have reported that NIC stimulates c-Fos expression in the brainstem. Whether there is a causal relationship between NIC effects on ingestion and its effect on brainstem neurons is uncertain, however we hypothesized that blocking NIC action in the brainstem would prevent, to some extent, the hypophagic effects of NIC. In the present study, cannulas were placed in the fourth ventricle of rats. A dose of NIC or saline was injected i.p. in four equal injections during the dark phase for four days. At the start of the second day of injections the NIC receptor antagonist mecamylamine (MEC) or artificial cerebrospinal fluid (a-CSF) was infused intracerebroventricularly (i.c.v.). Thus, four experimental groups were examined: a-CSF + SAL; a-CSF + NIC; MEC + SAL; MEC + NIC. Meal patterns were recorded using a computerized system and water intake and body weight were measured daily. Peripheral NIC injections suppressed food intake by decreasing meal size, whereas infusion of the NIC receptor antagonist MEC (4 microg) into the fourth ventricle blocked the NIC suppression of food intake. Moreover, the MEC effect was due primarily to an increase in dark phase meal size, which suggests neurons localized to the brainstem transmit NIC signals that regulate feeding behavior by affecting meal size.
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Affiliation(s)
- Guoqiang Guan
- Department of Biomedical Science, Baylor College of Dentistry, The Texas A&M University System Health Science Center, Dallas, TX 75246, USA
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33
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Ku YH, Li YH. Inhibitory effect of atriopeptinergic neurons in AV3V region on angiotensinII pressor system in rat brain. Peptides 2004; 25:615-20. [PMID: 15165717 DOI: 10.1016/j.peptides.2004.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Accepted: 02/20/2004] [Indexed: 11/24/2022]
Abstract
In the central nervous system and the periphery, atrial natriuretic peptide (ANP) and angiotensinII(AngII) play important and opposite roles in regulating blood pressure and fluid electrolyte balance. Their central mechanisms are unclear. In the brain the anteroventral third ventricle region (AV3V) contains the most prominent collection of atriopeptin-like immunoreactive perikarya. Our previous studies show that: (1) AV3V stimulation by glutamate produces a fall in blood pressure; (2) there is an AngII pressor system composed of the lateral hypothalamus/perifornical region (LH/PF), subfornical organ (SFO), nucleus paraventricularis (NPV) and rostral ventrolateral medulla (RVL). The present study was to examine whether ANPergic projections from the AV3V could act on nuclei involved in the above-mentioned AngII pressor system. Here we demonstrate that: (1) Injection of atriopeptinIII into the LH/PF, SFO, NPV, or RVL induces a depressor response; whereas injection of normal saline has no effect. (2) Pre-injection of A 71915 (an atriopeptinIII antagonist) into the LH/PF, SFO, NPV, or RVL reverses the depressor response of the AV3V to glutamate (Glu). The results suggest that excitation of atriopeptinergic neurons in the AV3V by Glu produces an inhibitory effect on each nucleus in the LH/PF-SFO-NPV-RVL AngII pressor system.
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Affiliation(s)
- Yun-Hui Ku
- Department of Physiology, Peking University Health Science Center, Beijing 100083, PR China.
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34
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Jacobowitz DM, Kresse A, Skofitsch G. Galanin in the brain: chemoarchitectonics and brain cartography--a historical review. Peptides 2004; 25:433-64. [PMID: 15134866 DOI: 10.1016/j.peptides.2004.02.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We present a review of galanin in the brain from a historical perspective of the development of "chemoarchitectonics" and "brain cartography" accomplished in the Histopharmacology Section at the National Institutes of Health. It was the mapping of potential brain neuroregulators that served as a springboard of ideas from which behavioral studies emanate. The integration of the known localization of neurotransmitter/neuromodulatory nerves ("chemoarchitectonic maps") and receptor binding sites with biochemical data derived from brain micropunches coupled with behavioral analysis at the level of discrete brain allows one to define the anatomical circuits which support behavioral changes and which ultimately will improve our understanding of mental disorders.
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Affiliation(s)
- David M Jacobowitz
- Laboratory of Clinical Science, National Institute of Mental Health, National Institues of Health, Bethesda, MD 20892, USA.
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35
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Jacobowitz DM, Kallarakal AT. Flotillin-1 in the substantia nigra of the Parkinson brain and a predominant localization in catecholaminergic nerves in the rat brain. Neurotox Res 2004; 6:245-57. [PMID: 15545008 DOI: 10.1007/bf03033435] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The substantia nigra cells of a normal and Parkinson's disease human brain were obtained by the micropunch procedure and total RNA was isolated. Differential display RT-PCR of the total RNA revealed differentially expressed cDNAs that were identified by sequencing. This resulted in the identification of a panel of known and unknown differentially expressed genes. Complex I (NADH ubiquinone oxidoreductase) and Complex IV (cytochrome oxidase) whose expressions are decreased in Parkinson's disease were reduced in the Parkinson brain. Of the various differentially expressed genes, flotillin-1, also known as reggie-2, was of great interest to us. It is a relatively new protein which is an integral membrane component of lipid rafts and has been implicated in signal transduction pathway events. In situ hybridization histochemical studies with human and rat brain sections revealed the presence of this mRNA in discrete neuronal (and possibly glial) cells of the substantia nigra, locus coeruleus, cortex, hippocampus, hypothalamus, thalamus, motor nuclei, nucleus basalis, raphe nucleus, and other brain regions. Immunohistochemical studies revealed that flotillin-1 is not present in all the regions where the message was found. In the rat brain, the most prominent observation was the revelation of all catecholamine cells (dopamine, norepinephrine, epinephrine) by the flotillin-1 antibody (1:100 dilution). At a more concentrated dilution (1:10) other neuronal cells (e.g., cortex, thalamus, hindbrain) were observed. At both dilutions dense dopaminergic fibers were observed in the rat caudate-putamen, nigrostriatal tract, and substantia nigra. It is significant that there is an increased gene expression of flotillin-1 in the Parkinson substantia nigra/ventral tegmental area. The role of flotillin in these cells is unclear although it is interesting that the reggie-2/flotillin-1 gene was upregulated during retinal axon regeneration in the goldfish visual pathway (Schulte et al., Development 124:577-87, 1997) which suggests that flotillin-1/reggie-2 might play a role in axonal growth from the remaining substantia nigra cells of the Parkinson brain.
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Affiliation(s)
- D M Jacobowitz
- Laboratory of Clinical Science, NIMH, NIH, Bethesda, MD 20892, USA.
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36
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Schulkin J. Mapping biochemical signals in the brain. Neurotox Res 2004; 6:xv-xxi. [PMID: 15614982 DOI: 10.1007/bf03033446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jay Schulkin
- Department of Physiology and Biophysics, Georgetown University School of Medicine, Washington, DC 20007, USA.
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37
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Leonard SK, Anderson CM, Lachowicz JE, Schulz DW, Kilts CD, Mailman RB. Amygdaloid D1 receptors are not linked to stimulation of adenylate cyclase. Synapse 2003; 50:320-33. [PMID: 14556237 DOI: 10.1002/syn.10272] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In contrast to the classic signal transduction of D1 dopamine receptors in striatum or molecular expression systems, it has been reported that D1 receptor agonists do not stimulate adenylate cyclase in homogenates of microdissected nuclei of the amygdaloid complex. This article examines this phenomenon in detail to determine if lack of cAMP signaling in the amygdaloid complex is an experimental artifact, or an indication of a marked difference from the well-studied basal ganglia terminal fields. Thus, whereas dopamine agonists failed to increase cAMP synthesis in the amygdala, forskolin, guanine nucleotides, or Mg2+ were able to stimulate adenylate cyclase activity in the same preparations. Under several different conditions, caudate preparations responded more robustly than amygdaloid preparations, while amygdala homogenates exhibited higher basal production of cAMP. Whereas the beta-adrenergic agonist isoproterenol was able to stimulate cAMP efflux in membranes from both the caudate and amygdala under a variety of tested conditions, neither dopamine nor fenoldopam (D1 agonist) could stimulate adenylate cyclase in the amygdala. Additionally, while manipulation of Ca2+ and calmodulin affected the differential actions of dopamine in the caudate, no change in these parameters restored sensitivity to dopamine in the amygdala. Together, these data challenge the commonly accepted notion that cAMP is a mandatory signaling pathway for D1 receptors. Because it is now proven that G protein-coupled receptors can signal promiscuously, elucidation of the non-cAMP-dependent signaling mechanisms resulting from D1 activation is clearly critical in understanding how this important receptor functions in situ.
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Affiliation(s)
- Sarah K Leonard
- Neuroscience Center, Departments of Psychiatry and Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7250, USA
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Otake K, Nakamura Y. Forebrain neurons with collateral projections to both the interstitial nucleus of the posterior limb of the anterior commissure and the nucleus of the solitary tract in the rat. Neuroscience 2003; 119:623-8. [PMID: 12809682 DOI: 10.1016/s0306-4522(03)00216-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The interstitial nucleus of the posterior limb of the anterior commissure (IPAC) receives inputs from several autonomic/limbic regions in the forebrain, including the agranular insular cortex, bed nucleus of the stria terminalis, the amygdaloid complex, and the lateral hypothalamic area. We sought to identify the distribution of afferent sources to the IPAC and to determine whether these IPAC projection fibers issue collaterals to the nucleus of the solitary tract (NTS), the principal relay of primary visceral afferents. Two fluorescent tracers, FluoroGold and FluoroRed, were centered stereotaxically on the IPAC and the NTS on chloral hydrate-anesthetized Sprague-Dawley rats. Although the majority of IPAC and NTS afferents were spatially segregated, small but substantial numbers of dually labeled neurons (three to four cells/section) were observed in the dorsal bank of the posterior agranular insular cortex, exclusively in layer V. Collateral projection neurons were also found in the posterior part of the lateral hypothalamic area (two to six cells/section). The branching projections identified here may represent a potential link between affective or motivated behavior and viscerosensory processing.
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Affiliation(s)
- K Otake
- Section of Neuroanatomy, Department of Systems Neuroscience, Division of Cognitive and Behavioral Medicine, Tokyo Medical and Dental University Graduate School, , Tokyo, 113-8519, Japan.
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Wiggins AK, Shen PJ, Gundlach AL. Atrial natriuretic peptide expression is increased in rat cerebral cortex following spreading depression: possible contribution to sd-induced neuroprotection. Neuroscience 2003; 118:715-26. [PMID: 12710979 DOI: 10.1016/s0306-4522(03)00006-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cortical spreading depression (CSD) is characterised by slowly propagating waves of cellular depolarization and depression and involves transient changes in blood flow, ion balance and metabolism. In cerebral ischaemia, peri-infarct CSD-like depolarization potentiates infarct growth, whereas preconditioning with a CSD episode protects against subsequent ischaemic insult. Thus, many of the long-lasting molecular changes that occur in CSD-affected tissue are presumed to be part of a 'neuroprotective cascade.' 3',5'-Cyclic guanosine monophosphate (cGMP) has been shown to be a neuroprotective mediator and the nitric oxide system, which increases cGMP production by soluble guanylate cyclase, is up-regulated by CSD. Atrial and C-type natriuretic peptide (ANP/CNP) are present in cerebral cortex and their actions are mediated via particulate guanylate cyclase receptors and cGMP production. Therefore, in further efforts to characterise the role of cGMP-related systems in CSD and neuroprotection, this study investigated possible changes in cortical natriuretic peptide expression following acute, unilateral CSD in rats. Using in situ hybridisation, significant 20-80% increases in ANP mRNA were detected in layers II and VI of ipsilateral cortex at 6 h and 1-14 days after CSD. Ipsilateral cortical levels were again equivalent to control contralateral values after 28 days. Assessment of cortical concentrations of ANP immunoreactivity by radioimmunoassay revealed a significant 57% increase at 7 days after CSD. Despite using a sensitive signal-amplification protocol, authentic ANP-like immunostaining was readily detected in subcortical nerve fibres, but was not reliably detected in normal or CSD-affected neocortex, suggesting the presence of very low levels, and/or active or differential processing of the peptide. Cortical CNP mRNA levels are not altered by CSD, indicating the specificity of the observed effects.Overall, these novel findings demonstrate a prolonged increase in cortical ANP expression after an acute episode of CSD. The overlap between the described time course of CSD-induced protection against ischaemic insult and demonstrated increases in ANP levels, suggest that ANP (like nitric oxide) may contribute to CSD-induced neuroprotection, via effects on cGMP production and other signal-transduction pathways.
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Affiliation(s)
- A K Wiggins
- Howard Florey Institute of Experimental Physiology and Medicine, Department of Medicine, Austin and Repatriation Medical Centre, The University of Melbourne, Victoria 3010, Australia
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Abstract
It has been proved that there are the subfornical organ (SFO)-nucleus paraventricularis (NPV)-rostral ventrolateral medulla (RVL) angiotension II (AngII) pressor system and the central amygdaloid nucleus (AC)-lateral hypothalamus/perifornical region (LH/PF) emotional pressor system in the brain. Because the LH/PF contains abundant AngII ergic neurons projecting to the SFO, the purpose of the present study was to examine whether the (SFO-NPV-RVL) AngII pressor system takes part in the AC-pressor response via AngII ergic neurons in the LH/PF. The results showed that (1) L-glutamate microinjection into the AC or LH/PF induced pressor responses. (2) Both the AC- and LH/PF-pressor responses could be reversed by preinjection of [Sar(1), Thr(8)]-angiotensin II (an antagonist of AngII) into either the SFO, NPV or RVL. Taken together with our previous findings that the projections of the CRF-ergic and SP-ergic neurons in the AC could activate the LH/PF, the above findings prove that: besides several known mechanisms of the brain AngII inducing pressor response, the (SFO-NPV-RVL) AngII pressor system also takes part in the AC-emotional pressor response via AngII ergic projections from the LH/PF to the SFO, which may be the neurophysiological basis of the brain AngII playing an important role in developing hypertension of the SHRs.
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Affiliation(s)
- Yun-Hui Ku
- Department of Physiology, Peking University Health Science Center, Beijing 100083, PR China.
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41
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Abstract
It has been shown that intracerebroventricular injection of urotensin II (UII)-induced hypotensive and bradycardiac responses. Here, we tested the cardiovascular roles of UII in different brain areas by microinjection of UII into the A1 and A2 areas (noradrenergic cells found in the lower part of the medulla that have been designated either A1 or A2 areas), the paraventricular and the arcuate nucleus. In urethane-anaesthetized rats, we observed that: (1) microinjection of UII into the A1 area induced dose-related depressor and bradycardiac responses; (2) mean arterial blood pressure (mABP) and heart rate (HR) did not change significantly after microinjection of UII into the A2 area; and (3) significant increases in mABP and HR were induced after microinjection of 10 pmol UII into either the paraventricular or arcuate nucleus. The above results suggest that UII, in different brain areas, plays different roles in cardiovascular regulation and the A1 area is a very important action site for UII in cardiovascular regulation.
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Affiliation(s)
- Yang Lu
- Department of Physiology, Health Science Center, Peking University, Beijing, PR China
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Lu Y, Chen W, Zou CJ. Interleukin-1 beta is involved in the pressor response of amygdaloid neurons excited by sodium glutamate. Neuroreport 2002; 13:559-62. [PMID: 11930180 DOI: 10.1097/00001756-200203250-00039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of interleukin-1beta in the paraventricular nucleus or caudal arcuate nucleus on hypertensive and tachycardiac responses induced by excitation of the central amygdaloid nucleus were studied. We observed that microinjection of sodium glutamate into central amygdaloid nucleus resulted in hypertension and tachycardia. Microinjection of interleukin-1beta into paraventricular nucleus or caudal arcuate nucleus induced significant pressor and tachycardiac responses while pretreatment with microinjection of rabbit anti-rat interleukin-1beta antibody into bilateral paraventricular nuclei or arcuate nuclei attenuated the hypertensive response induced by microinjection of 40 nmol sodium glutamate into central amygdaloid nucleus. The above results suggest that the pressor effect of central amygdaloid nucleus is mediated by interleukin-1beta in paraventricular nucleus or arcuate nucleus.
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Affiliation(s)
- Yang Lu
- Department of Physiology, Health Science Center, P.R. China
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43
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Abstract
Most forms of hypertension are associated with a wide variety of functional changes in the hypothalamus. Alterations in the following substances are discussed: catecholamines, acetylcholine, angiotensin II, natriuretic peptides, vasopressin, nitric oxide, serotonin, GABA, ouabain, neuropeptide Y, opioids, bradykinin, thyrotropin-releasing factor, vasoactive intestinal polypeptide, tachykinins, histamine, and corticotropin-releasing factor. Functional changes in these substances occur throughout the hypothalamus but are particularly prominent rostrally; most lead to an increase in sympathetic nervous activity which is responsible for the rise in arterial pressure. A few appear to be depressor compensatory changes. The majority of the hypothalamic changes begin as the pressure rises and are particularly prominent in the young rat; subsequently they tend to fluctuate and overall to diminish with age. It is proposed that, with the possible exception of the Dahl salt-sensitive rat, the hypothalamic changes associated with hypertension are caused by renal and intrathoracic cardiopulmonary afferent stimulation. Renal afferent stimulation occurs as a result of renal ischemia and trauma as in the reduced renal mass rat. It is suggested that afferents from the chest arise, at least in part, from the observed increase in left auricular pressure which, it is submitted, is due to the associated documented impaired ability to excrete sodium. It is proposed, therefore, that the hypothalamic changes in hypertension are a link in an integrated compensatory natriuretic response to the kidney's impaired ability to excrete sodium.
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Affiliation(s)
- H E de Wardener
- Department of Clinical Chemistry, Imperial College School of Medicine, Charing Cross Campus, London, United Kingdom.
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44
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Sánchez MS, Barontini M, Armando I, Celis ME. Correlation of increased grooming behavior and motor activity with alterations in nigrostriatal and mesolimbic catecholamines after alpha-melanotropin and neuropeptide glutamine-isoleucine injection in the rat ventral tegmental area. Cell Mol Neurobiol 2001; 21:523-33. [PMID: 11860189 DOI: 10.1023/a:1013871407464] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. We wished to further study the behavioral effects of alpha-melanotropin (alpha-MSH), melanin-concentrating hormone (MCH), and neuropeptide glutamine-isoleucine (NEI). 2. To this effect we administered alpha-MSH, MCH, and NEI in the ventral tegmental area of the rat, a structure where these neuropeptides are highly concentrated. To further elucidate the biochemical mechanisms of the behavioral effect of these neuropeptides, we determined the degree of grooming behavior and the levels of catecholamines. after neuropeptide administration. 3. We preselected those animals responding to the central injection of alpha-MSH with excessive grooming behavior. We administered the neuropeptides at the dose of 1 microg/0.5 microL, in each side of the ventral tegmental area, bilaterally. We studied grooming behavior, locomotor activity, and total behavior scores, 30 and 65 min after administration of the peptides. 4. Three groups of animals were decapitated immediately after the injection of the neuropeptides, and 30 or 65 min after injection. We measured dopamine (DA), noradrenaline (NA), and the dopac/dopamine ratio (DOPAC/DA) to determine steady state levels of catecholamines and an indirect measure of DA release and metabolism, respectively. 5. Injections of alpha-MSH produced significant elevations in grooming behavior, locomotor activity, and total behavior scores, both 30 and 65 min after peptide administration. This was correlated with significant decreases in DA content, increases in DOPAC content, and increases in the DOPAC/DA ratio. In the caudate putamen, changes in catecholamines occurred both at 30 and 65 min after injection. In the nucleus accumbens, changes were present at 65 min after injection. Conversely, there were no alterations in NA content, either in the caudate putamen or in the nucleus accumbens, at any time after the injection. 6. Injections of NEI resulted in significant elevations in grooming behavior, locomotor activity, and total behavior scores, both 30 and 65 min after peptide administration. This was correlated with increased DOPAC/DA ratio in the nucleus caudatus but not in the nucleus accumbens. Conversely, NEI produced increased NA concentrations in the nucleus accumbens, but not in the nucleus caudatus. 7. Injections of MCH did not produce significant changes in behavior or significant changes in nucleus caudatus or nucleus accumbens catecholamines. 8. Our results indicate (a) There is a correlation with alterations in behavior as induced for the neuropeptides injected here, and changes in extrapyramidal catecholamines. (b) There is a correlation between alterations in behavior and increases in DOPAC/DA ratio in the nucleus caudatus. (c) There is a correlation between alterations in behavior and alterations in catecholamines in the nucleus accumbens. In the nucleus accumbens, DOPAC/DA ratio is changed after alpha-MSH, and NA ratio is changed after NEI injection. (d) Absence of alterations in extrapyramidal catecholamines, and in particular in catecholamines in the nucleus accumbens, correlates with absence of behavioral alterations after neuropeptide administration to the ventral tegmental area. 9. In conclusion, the behavioral effect of exogenous administration of neuropeptides in the ventral tegmental area is peptide-specific, and is probably associated with alterations in catecholamine metabolism and release in the nucleus caudatus and the nucleus accumbens. Both alpha-MSH and NEI seem to stimulate the nigrostriatal DA system. While alpha-MSH appears to stimulate the mesolimbic DA system as well, NEI may exert its actions not through the DA, but through the NA mesolimbic system. The precise contribution of DA and NA, and the relative role of the nucleus caudatus and nucleus accumbens in these behaviors remain to be elucidated.
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Affiliation(s)
- M S Sánchez
- Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
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Ku YH, Chang YZ. Beta-endorphin- and GABA-mediated depressor effect of specific electroacupuncture surpasses pressor response of emotional circuit. Peptides 2001; 22:1465-70. [PMID: 11514030 DOI: 10.1016/s0196-9781(01)00467-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It has been proved that input of specific electroacupuncture (EA) can activate beta-endorphin(beta-EP)ergic and noradrenergic neurons projecting to the rostral ventrolateral medulla (RVL), the latter acting upon the RVL-GABAergic interneurons, thereby produce depressor effect. The present study further shows that: (1) The EA depressor effect is strong enough to surpass the pressor response of the AC (nucleus amygdaloideus centralis)-emotional circuit, (2) both beta-endorphin (beta-EP) and GABA in the RVL mediate the EA antagonistic effect, (3) the EA effect does not take place in the AC and paraventricular nucleus (two key nuclei besides the RVL, which also have beta-EPergic input) in the emotional circuit.
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Affiliation(s)
- Y H Ku
- Department of Physiology, Health Science Center, Peking University, 100083, Beijing, People's Republic of China.
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Pérez SE, Yáñez J, Marín O, Anadón R, González A, Rodríguez-Moldes I. Distribution of choline acetyltransferase (ChAT) immunoreactivity in the brain of the adult trout and tract-tracing observations on the connections of the nuclei of the isthmus. J Comp Neurol 2000; 428:450-74. [PMID: 11074445 DOI: 10.1002/1096-9861(20001218)428:3<450::aid-cne5>3.0.co;2-t] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The distribution of cholinergic neurons and fibers was studied in the brain and rostral spinal cord of the brown trout and rainbow trout by using an antiserum against the enzyme choline acetyltransferase (ChAT). Cholinergic neurons were observed in the ventral telencephalon, preoptic region, habenula, thalamus, hypothalamus, magnocellular superficial pretectal nucleus, optic tectum, isthmus, cranial nerve motor nuclei, and spinal cord. In addition, new cholinergic groups were detected in the vascular organ of the lamina terminalis, the parvocellular and magnocellular parts of the preoptic nucleus, the anterior tuberal nucleus, and a mesencephalic tegmental nucleus. The presence of ChAT in the magnocellular neurosecretory system of trout suggests that acetylcholine is involved in control of hormone release by neurosecretory terminals. In order to characterize the several cholinergic nuclei observed in the isthmus of trout, their projections were studied by application of 1,1;-dioctadecyl-3,3,3;, 3;-tetramethylindocarbocyanine perchlorate (DiI) to selected structures of the brain. The secondary gustatory nucleus projected mainly to the lateral hypothalamic lobes, whereas the nucleus isthmi projected to the optic tectum and parvocellular superficial pretectal nucleus, as previously described in other teleost groups. In addition, other isthmic cholinergic nuclei of trout may be homologs of the mesopontine system of mammals. We conclude that the cholinergic systems of teleosts show many primitive features that have been preserved during evolution, together with characteristics exclusive to the group.
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Affiliation(s)
- S E Pérez
- Department of Cell and Molecular Biology, Faculty of Sciences, University of A Coruña, 15071-A Coruña, Spain
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De Parada MP, Parada MA, Rada P, Hernandez L, Hoebel BG. Dopamine-acetylcholine interaction in the rat lateral hypothalamus in the control of locomotion. Pharmacol Biochem Behav 2000; 66:227-34. [PMID: 10880673 DOI: 10.1016/s0091-3057(99)00244-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pharmacological, neurochemical, and behavioral techniques were used to characterize DA-ACh interaction within the lateral hypothalamus (LH) in the context of locomotion, feeding behavior, and reinforcement. In Experiment 1, the muscarinic agonist carbachol injected in the LH increased locomotor activity in proportion to dose. In Experiment 2, the same doses of carbachol proportionately increased exctracellular DA in the nucleus accumbens (Nac) as monitored by brain microdialysis. Dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) also increased. In Experiment 3, LH infusion by reverse microdialysis of the D(2) receptor blocker sulpiride released ACh in the LH in a dose-response manner. This suggested that sulpiride disinhibits ACh release via D(2) receptors in the LH and thereby facilitates behavior. Confirming this in Experiment 4, local LH atropine 5 min before sulpiride suppressed the locomotor response to sulpiride for about 20 min. These results suggest that sulpiride acts in the LH by disinhibiting a hypothalamic locomotor mechanism that is cholinergically driven and connected with the mesoaccumbens dopamine pathway. Given prior results that local sulpiride in the LH can induce hyperphagia and reward, this system may be involved in searching for food and rewarding feeding behavior. In conclusion, DA acts in the LH via D(2) receptors to inhibit cholinergic neurons or terminals that are part of an approach system for eating.
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Affiliation(s)
- M P De Parada
- Los Andes University, Department of Physiology, School of Medicine, 5101-A, Mérida, Venezuela
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Wu JS, Ku YH, Li LS, Lu YC, Ding X, Wang YG. Corticotropin releasing factor and substance P mediate the nucleus amygdaloideus centralis-nucleus ventromedialis-nucleus dorsomedialis pressor system. Brain Res 1999; 842:392-8. [PMID: 10526135 DOI: 10.1016/s0006-8993(99)01862-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Prolonged emotional stress is an important factor in the development of neurogenic hypertension, but its mechanism is still unclear. The purpose of the present study is to analyze the possible neural basis of hypertension induced by prolonged emotional stress. In the brain many nuclei are involved in emotional reaction, stress or defense response; among them the nucleus amygdaloideus centralis (AC) is the most important one which widely connects with other nuclei controlling emotion and stress, such as nucleus ventromedialis (NVM), nucleus dorsomedialis (NDM), nucleus paraventricularis (NPV) etc. These nuclei contain corticotropin releasing factor (CRF)- and substance P (SP)-immunoreactive cell bodies, nerve terminals and corresponding receptors. Our previous and present studies showed that microinjection of CRF or SP into these nuclei induced pressor responses. These data imply that excitation of the AC can activate many nuclei controlling emotion and stress via CRF and SP, and excessive activities of these nuclei may be the neural basis of hypertension induced by prolonged emotional stress. The present study revealed that (1) the AC pressor response to glutamate (Glu) could be reduced by preinjection of CRF antagonist (alpha-Helical CRF[9-41] or SP antagonist ([D-Pro(2), D-Phe(7), D-Trp(9)]-substance P) into bilateral NVM, (2) the NVM pressor response to Glu were decreased by pretreatment of the NDM with CRF- or SP-antagonist, (3) the AC-, NVM- or NDM-pressor responses were all attenuated by preinjection of CRF- or SP-antagonist into bilateral NPV or rostral ventrolateral medulla (RVL). The results indicate that excitation of the AC can indirectly activate the NPV and RVL to evoke pressor response via the NVM-NDM, CRF and SP are transmitters in each connection of this pathway; this is one component of the mechanism underlying the AC pressor response. Taken together with the findings of our previous studies, it provides neurophysiological basis for the above-mentioned implications.
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Affiliation(s)
- J S Wu
- Department of Physiology, Beijing Medical University, Beijing, China.
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Schuerger RJ, Balaban CD. Organization of the coeruleo-vestibular pathway in rats, rabbits, and monkeys. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1999; 30:189-217. [PMID: 10525175 DOI: 10.1016/s0165-0173(99)00015-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Inputs from locus coeruleus (LC) appear to be important for altering sensorimotor responses in situations requiring increase vigilance or alertness. This study documents the organization of coeruleo-vestibular pathways in rats, rabbits and monkeys. A lateral descending noradrenergic bundle (LDB) projects from LC to the superior vestibular nucleus (SVN) and rostral lateral vestibular nucleus (LVN). A medial descending noradrenergic bundle (MDB) projects from LC to LVN, the medial vestibular nucleus (MVN), group y and rostral nucleus prepositus hypoglossi (rNPH). There is a characteristic, specific pattern of innervation of vestibular nuclear regions across the three species. A quantitative analysis revealed four distinct innervation density levels (minimal, low, intermediate and high) across the vestibular nuclei. The densest plexuses of noradrenergic fibers were observed in the SVN and LVN. Less dense innervation was observed in the MVN, and minimal innervation was observed in the inferior vestibular nucleus (IVN). In monkeys and rabbits, rostral MVN contained a higher innervation density than the rat MVN. In monkeys, the rNPH also contained a dense plexus of fibers. Selective destruction of terminal LC projections (distal axons and terminals) by the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) resulted in a dramatic reduction of immunoreactive fibers within the vestibular nuclear complex of rats, suggesting that the source of these immunoreactive fibers is LC. Retrograde tracer injections into the vestibular nuclei resulted in labeled cells in the ipsilateral, caudal LC and adjacent nucleus subcoeruleus. It is hypothesized that the regional differences in noradrenergic innervation are a substrate for differentially altering vestibulo-ocular and vestibulo-spinal responses during changes in alertness or vigilance.
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Affiliation(s)
- R J Schuerger
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA.
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50
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Abstract
In urethane-anesthetized rats, microinjection of angiotensin II (AII) into either the subfornical organ (SFO), nucleus paraventricularis (NPV), or rostral ventrolateral medulla (RVL), respectively, all induced pressor responses, but the heart rate remained unchanged. Preinjection of [Sar1, Thr8]-angiotensin II (ST-AII, an AII antagonist) into bilateral NPV blocked the SFO-pressor response to AII. Bilateral RVL pretreated with ST-All markedly attenuated the pressor response of the SFO or NPV to AII. Hexamethonium or methyl atropine (IV) also reduced the SFO-pressor response. The results show that All can activate the SFO, NPV, and RVL successively, thereby inducing the pressor response; both excitation of sympathetic nerves and inhibition of the cardiac vagus are involved in this response.
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Affiliation(s)
- Y H Ku
- Department of Physiology, Beijing Medical University, China
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