1
|
Caligiore D, Montedori F, Buscaglione S, Capirchio A. Increasing Serotonin to Reduce Parkinsonian Tremor. Front Syst Neurosci 2021; 15:682990. [PMID: 34354572 PMCID: PMC8331097 DOI: 10.3389/fnsys.2021.682990] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/21/2021] [Indexed: 01/07/2023] Open
Abstract
While current dopamine-based drugs seem to be effective for most Parkinson's disease (PD) motor dysfunctions, they produce variable responsiveness for resting tremor. This lack of consistency could be explained by considering recent evidence suggesting that PD resting tremor can be divided into different partially overlapping phenotypes based on the dopamine response. These phenotypes may be associated with different pathophysiological mechanisms produced by a cortical-subcortical network involving even non-dopaminergic areas traditionally not directly related to PD. In this study, we propose a bio-constrained computational model to study the neural mechanisms underlying a possible type of PD tremor: the one mainly involving the serotoninergic system. The simulations run with the model demonstrate that a physiological serotonin increase can partially recover dopamine levels at the early stages of the disease before the manifestation of overt tremor. This result suggests that monitoring serotonin concentration changes could be critical for early diagnosis. The simulations also show the effectiveness of a new pharmacological treatment for tremor that acts on serotonin to recover dopamine levels. This latter result has been validated by reproducing existing data collected with human patients.
Collapse
Affiliation(s)
- Daniele Caligiore
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Francesco Montedori
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Silvia Buscaglione
- Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit (NeXT), Campus Bio-Medico University, Rome, Italy
| | - Adriano Capirchio
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| |
Collapse
|
2
|
Best J, Duncan W, Sadre-Marandi F, Hashemi P, Nijhout HF, Reed M. Autoreceptor control of serotonin dynamics. BMC Neurosci 2020; 21:40. [PMID: 32967609 PMCID: PMC7509944 DOI: 10.1186/s12868-020-00587-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/29/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Serotonin is a neurotransmitter that has been linked to a wide variety of behaviors including feeding and body-weight regulation, social hierarchies, aggression and suicidality, obsessive compulsive disorder, alcoholism, anxiety, and affective disorders. Full understanding involves genomics, neurochemistry, electrophysiology, and behavior. The scientific issues are daunting but important for human health because of the use of selective serotonin reuptake inhibitors and other pharmacological agents to treat disorders. This paper presents a new deterministic model of serotonin metabolism and a new systems population model that takes into account the large variation in enzyme and transporter expression levels, tryptophan input, and autoreceptor function. RESULTS We discuss the steady state of the model and the steady state distribution of extracellular serotonin under different hypotheses on the autoreceptors and we show the effect of tryptophan input on the steady state and the effect of meals. We use the deterministic model to interpret experimental data on the responses in the hippocampus of male and female mice, and to illustrate the short-time dynamics of the autoreceptors. We show there are likely two reuptake mechanisms for serotonin and that the autoreceptors have long-lasting influence and compare our results to measurements of serotonin dynamics in the substantia nigra pars reticulata. We also show how histamine affects serotonin dynamics. We examine experimental data that show very variable response curves in populations of mice and ask how much variation in parameters in the model is necessary to produce the observed variation in the data. Finally, we show how the systems population model can potentially be used to investigate specific biological and clinical questions. CONCLUSIONS We have shown that our new models can be used to investigate the effects of tryptophan input and meals and the behavior of experimental response curves in different brain nuclei. The systems population model incorporates individual variation and can be used to investigate clinical questions and the variation in drug efficacy. The codes for both the deterministic model and the systems population model are available from the authors and can be used by other researchers to investigate the serotonergic system.
Collapse
Affiliation(s)
- Janet Best
- Department of Mathematics, The Ohio State University, 231 W 18th Ave., Columbus, OH 43210 USA
| | - William Duncan
- Department of Mathematics, Duke University, Durham, NC 27708 USA
| | | | - Parastoo Hashemi
- Department of Bioengineering, Imperial College, London, SW7 2AZ UK
| | | | - Michael Reed
- Department of Mathematics, Duke University, Durham, NC 27708 USA
| |
Collapse
|
3
|
Rissardo JP, Caprara ALF. The Link Between Amitriptyline and Movement Disorders: Clinical Profile and Outcome. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2020. [PMID: 32419008 DOI: 10.47102/annals-acadmed.sg.202023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Amitriptyline (AMT) is a tricyclic antidepressant. In this review, we evaluate the clinical and epidemiological profile, pathological mechanisms and management of AMT-associated movement disorders. MATERIALS AND METHODS A search for relevant reports in 6 databases was performed. Studies that reported patients developed only ataxia or tremor after AMT use were excluded. RESULTS A total of 48 reports on 200 cases were found. AMT-associated movement disorders included myoclonus (n = 26), dyskinesia (n = 11), dystonia (n = 8), stutter (n = 5), akathisia (n = 3) and restless legs syndrome (n = 1). For less well-defined cases, 99 patients had dyskinesia, 19 had psychomotor disturbances, 3 had myoclonus, 11 had dystonia, 12 had Parkinsonism and 1 each had akathisia and extrapyramidal symptoms. Mean and standard deviation (SD) and median ages were 45.40 years (SD 16.78) and 40 years (range 3.7-82 years), respectively. Over half were women (58.13%) and the most common indication was depression. Mean and median AMT doses were 126 mg (SD 128.76) and 75 mg (range 15-800 mg), respectively. In 68% of patients, onset of movement disorders was <1 month; time from AMT withdrawal to complete recovery was <1 month in 70% of cases. A weak negative linear correlation (r = -0.0904) was found between onset of movement disorders and AMT dose. AMT withdrawal was the most common treatment. CONCLUSION Amitriptyline is associated with various movement disorders, particularly myoclonus, dystonia and dyskinesias. Stutters and restless legs syndrome are some of the less common associations.
Collapse
|
4
|
Neville V, Nakagawa S, Zidar J, Paul ES, Lagisz M, Bateson M, Løvlie H, Mendl M. Pharmacological manipulations of judgement bias: A systematic review and meta-analysis. Neurosci Biobehav Rev 2020; 108:269-286. [PMID: 31747552 PMCID: PMC6966323 DOI: 10.1016/j.neubiorev.2019.11.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 11/13/2019] [Accepted: 11/13/2019] [Indexed: 01/11/2023]
Abstract
Validated measures of animal affect are crucial to research spanning numerous disciplines. Judgement bias, which assesses decision-making under ambiguity, is a promising measure of animal affect. One way of validating this measure is to administer drugs with affect-altering properties in humans to non-human animals and determine whether the predicted judgement biases are observed. We conducted a systematic review and meta-analysis using data from 20 published research articles that use this approach, from which 557 effect sizes were extracted. Pharmacological manipulations overall altered judgement bias at the probe cues as predicted. However, there were several moderating factors including the neurobiological target of the drug, whether the drug induced a relatively positive or negative affective state in humans, dosage, and the presented cue. This may partially reflect interference from adverse effects of the drug which should be considered when interpreting results. Thus, the overall pattern of change in animal judgement bias appears to reflect the affect-altering properties of drugs in humans, and hence may be a valuable measure of animal affective valence.
Collapse
Affiliation(s)
- Vikki Neville
- Centre for Behavioural Biology, Bristol Veterinary School, University of Bristol, Langford BS40 5DU, United Kingdom.
| | - Shinichi Nakagawa
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Sydney, NSW 2052, Australia
| | - Josefina Zidar
- The Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Elizabeth S Paul
- Centre for Behavioural Biology, Bristol Veterinary School, University of Bristol, Langford BS40 5DU, United Kingdom
| | - Malgorzata Lagisz
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Sydney, NSW 2052, Australia
| | - Melissa Bateson
- Institute of Neuroscience and Centre for Behaviour and Evolution, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Hanne Løvlie
- The Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Michael Mendl
- Centre for Behavioural Biology, Bristol Veterinary School, University of Bristol, Langford BS40 5DU, United Kingdom
| |
Collapse
|
5
|
Huang KW, Ochandarena NE, Philson AC, Hyun M, Birnbaum JE, Cicconet M, Sabatini BL. Molecular and anatomical organization of the dorsal raphe nucleus. eLife 2019; 8:e46464. [PMID: 31411560 PMCID: PMC6726424 DOI: 10.7554/elife.46464] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/13/2019] [Indexed: 12/20/2022] Open
Abstract
The dorsal raphe nucleus (DRN) is an important source of neuromodulators and has been implicated in a wide variety of behavioral and neurological disorders. The DRN is subdivided into distinct anatomical subregions comprised of multiple cell types, and its complex cellular organization has impeded efforts to investigate the distinct circuit and behavioral functions of its subdomains. Here we used single-cell RNA sequencing, in situ hybridization, anatomical tracing, and spatial correlation analysis to map the transcriptional and spatial profiles of cells from the mouse DRN. Our analysis of 39,411 single-cell transcriptomes revealed at least 18 distinct neuron subtypes and 5 serotonergic neuron subtypes with distinct molecular and anatomical properties, including a serotonergic neuron subtype that preferentially innervates the basal ganglia. Our study lays out the molecular organization of distinct serotonergic and non-serotonergic subsystems, and will facilitate the design of strategies for further dissection of the DRN and its diverse functions.
Collapse
Affiliation(s)
- Kee Wui Huang
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Nicole E Ochandarena
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Adrienne C Philson
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Minsuk Hyun
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Jaclyn E Birnbaum
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Marcelo Cicconet
- Image and Data Analysis CoreHarvard Medical SchoolBostonUnited States
| | - Bernardo L Sabatini
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| |
Collapse
|
6
|
Caligiore D, Mannella F, Baldassarre G. Different Dopaminergic Dysfunctions Underlying Parkinsonian Akinesia and Tremor. Front Neurosci 2019; 13:550. [PMID: 31191237 PMCID: PMC6549580 DOI: 10.3389/fnins.2019.00550] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/13/2019] [Indexed: 11/15/2022] Open
Abstract
Although the occurrence of Parkinsonian akinesia and tremor is traditionally associated to dopaminergic degeneration, the multifaceted neural processes that cause these impairments are not fully understood. As a consequence, current dopamine medications cannot be tailored to the specific dysfunctions of patients with the result that generic drug therapies produce different effects on akinesia and tremor. This article proposes a computational model focusing on the role of dopamine impairments in the occurrence of akinesia and resting tremor. The model has three key features, to date never integrated in a single computational system: (a) an architecture constrained on the basis of the relevant known system-level anatomy of the basal ganglia-thalamo-cortical loops; (b) spiking neurons with physiologically-constrained parameters; (c) a detailed simulation of the effects of both phasic and tonic dopamine release. The model exhibits a neural dynamics compatible with that recorded in the brain of primates and humans. Moreover, it suggests that akinesia might involve both tonic and phasic dopamine dysregulations whereas resting tremor might be primarily caused by impairments involving tonic dopamine release and the responsiveness of dopamine receptors. These results could lead to develop new therapies based on a system-level view of the Parkinson's disease and targeting phasic and tonic dopamine in differential ways.
Collapse
Affiliation(s)
- Daniele Caligiore
- National Research Council, Institute of Cognitive Sciences and Technologies, Rome, Italy
| | - Francesco Mannella
- National Research Council, Institute of Cognitive Sciences and Technologies, Rome, Italy
| | - Gianluca Baldassarre
- National Research Council, Institute of Cognitive Sciences and Technologies, Rome, Italy
| |
Collapse
|
7
|
Imamura Y, Shinozaki T, Okada-Ogawa A, Noma N, Shinoda M, Iwata K, Wada A, Abe O, Wang K, Svensson P. An updated review on pathophysiology and management of burning mouth syndrome with endocrinological, psychological and neuropathic perspectives. J Oral Rehabil 2019; 46:574-587. [PMID: 30892737 DOI: 10.1111/joor.12795] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/19/2019] [Accepted: 03/12/2019] [Indexed: 12/17/2022]
Abstract
Burning mouth syndrome (BMS) is a chronic oro-facial pain disorder of unknown cause. It is more common in peri- and post-menopausal women, and sex hormone dysregulation is believed to be an important causative factor. Psychosocial events often trigger or exacerbate symptoms, and persons with BMS appear to be predisposed towards anxiety and depression. Atrophy of small nerve fibres in the tongue epithelium has been reported, and potential neuropathic mechanisms for BMS are now widely investigated. Historically, BMS was thought to comprise endocrinological, psychosocial and neuropathic components. Neuroprotective steroids and glial cell line-derived neurotrophic factor family ligands may have pivotal roles in the peripheral mechanisms associated with atrophy of small nerve fibres. Denervation of chorda tympani nerve fibres that innervate fungiform buds leads to alternative trigeminal innervation, which results in dysgeusia and burning pain when eating hot foods. With regard to the central mechanism of BMS, depletion of neuroprotective steroids alters the brain network-related mood and pain modulation. Peripheral mechanistic studies support the use of topical clonazepam and capsaicin for the management of BMS, and some evidence supports the use of cognitive behavioural therapy. Hormone replacement therapy may address the causes of BMS, although adverse effects prevent its use as a first-line treatment. Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) may have important benefits, and well-designed controlled studies are expected. Other treatment options to be investigated include brain stimulation and TSPO (translocator protein 18 kDa) ligands.
Collapse
Affiliation(s)
- Yoshiki Imamura
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Takahiro Shinozaki
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Akiko Okada-Ogawa
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Noboru Noma
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Masahiro Shinoda
- Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan.,Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Koichi Iwata
- Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan.,Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Akihiko Wada
- Department of Radiology, Faculty of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kelun Wang
- Department of Health Science and Technology, Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark
| | - Peter Svensson
- Department of Dentistry and Oral Health, Section for Orofacial Pain and Jaw Function, Aarhus University, Aarhus, Denmark
| |
Collapse
|
8
|
Wong-Lin K, Wang DH, Moustafa AA, Cohen JY, Nakamura K. Toward a multiscale modeling framework for understanding serotonergic function. J Psychopharmacol 2017; 31:1121-1136. [PMID: 28417684 PMCID: PMC5606304 DOI: 10.1177/0269881117699612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Despite its importance in regulating emotion and mental wellbeing, the complex structure and function of the serotonergic system present formidable challenges toward understanding its mechanisms. In this paper, we review studies investigating the interactions between serotonergic and related brain systems and their behavior at multiple scales, with a focus on biologically-based computational modeling. We first discuss serotonergic intracellular signaling and neuronal excitability, followed by neuronal circuit and systems levels. At each level of organization, we will discuss the experimental work accompanied by related computational modeling work. We then suggest that a multiscale modeling approach that integrates the various levels of neurobiological organization could potentially transform the way we understand the complex functions associated with serotonin.
Collapse
Affiliation(s)
- KongFatt Wong-Lin
- Intelligent Systems Research Centre, School of Computing and Intelligent Systems, University of Ulster, Magee Campus, Derry~Londonderry, UK
| | - Da-Hui Wang
- School of Systems Science, and National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Ahmed A Moustafa
- School of Social Sciences and Psychology, and Marcs Institute for Brain and Behaviour, University of Western Sydney, Sydney, Australia
| | - Jeremiah Y Cohen
- Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Kae Nakamura
- Department of Physiology, Kansai Medical University, Hirakata, Osaka, Japan
| |
Collapse
|
9
|
Kawashima T. The role of the serotonergic system in motor control. Neurosci Res 2017; 129:32-39. [PMID: 28774814 DOI: 10.1016/j.neures.2017.07.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/11/2017] [Accepted: 07/13/2017] [Indexed: 01/20/2023]
Abstract
The serotonergic system in the vertebrate brain is implicated in various behaviors and diseases. Its involvement in motor control has been studied for over half a century, but efforts to build a unified model of its functions have been hampered due to the complexity of serotonergic neuromodulation. This review summarizes the anatomical structure of the serotonergic system, its afferent and efferent connections to other brain regions, and recent insights into the sensorimotor computations in the serotonergic system, and considers future research directions into the roles of serotonergic system in motor control.
Collapse
Affiliation(s)
- Takashi Kawashima
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA.
| |
Collapse
|
10
|
Cullen M, Wong-Lin K. Integrated dopaminergic neuronal model with reduced intracellular processes and inhibitory autoreceptors. IET Syst Biol 2016; 9:245-58. [PMID: 26577159 DOI: 10.1049/iet-syb.2015.0018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Dopamine (DA) is an important neurotransmitter for multiple brain functions, and dysfunctions of the dopaminergic system are implicated in neurological and neuropsychiatric disorders. Although the dopaminergic system has been studied at multiple levels, an integrated and efficient computational model that bridges from molecular to neuronal circuit level is still lacking. In this study, the authors aim to develop a realistic yet efficient computational model of a dopaminergic pre-synaptic terminal. They first systematically perturb the variables/substrates of an established computational model of DA synthesis, release and uptake, and based on their relative dynamical timescales and steady-state changes, approximate and reduce the model into two versions: one for simulating hourly timescale, and another for millisecond timescale. They show that the original and reduced models exhibit rather similar steady and perturbed states, whereas the reduced models are more computationally efficient and illuminate the underlying key mechanisms. They then incorporate the reduced fast model into a spiking neuronal model that can realistically simulate the spiking behaviour of dopaminergic neurons. In addition, they successfully include autoreceptor-mediated inhibitory current explicitly in the neuronal model. This integrated computational model provides the first step toward an efficient computational platform for realistic multiscale simulation of dopaminergic systems in in silico neuropharmacology.
Collapse
Affiliation(s)
- Maell Cullen
- Intelligent Systems Research Centre, University of Ulster, Magee Campus, Northland Road, L'Derry BT48 7JL, Northern Ireland, UK
| | - KongFatt Wong-Lin
- Intelligent Systems Research Centre, University of Ulster, Magee Campus, Northland Road, L'Derry BT48 7JL, Northern Ireland, UK.
| |
Collapse
|
11
|
L-Dopa and Brain Serotonin System Dysfunction. TOXICS 2015; 3:75-88. [PMID: 29056652 PMCID: PMC5634697 DOI: 10.3390/toxics3010075] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 02/16/2015] [Accepted: 02/26/2015] [Indexed: 12/30/2022]
Abstract
L-dopa is used to treat the motor symptoms associated with Parkinson's disease, a neurodegenerative movement disorder characterized by a loss of dopamine neurons. L-dopa is the precursor to dopamine and crosses the blood-brain barrier to increase dopamine neurotransmission. This review will focus on the findings that dopamine produced from L-dopa is mediated in part by serotonin neurons. Direct evidence will be provided that increases in dopamine cause oxidative stress and damage serotonin neurons. Similarly, chronic L-dopa produces deficits in serotonin neurotransmission, including decreases in both serotonin cell bodies within the dorsal raphe and serotonin neurotransmitter concentrations in several forebrain regions. Since serotonin is involved in many important physiological processes including mood and cognition, L-dopa induced serotonin deficits may play a role in the side-effect symptoms observed in Parkinson's disease patients treated with L-dopa.
Collapse
|
12
|
Pollak Dorocic I, Fürth D, Xuan Y, Johansson Y, Pozzi L, Silberberg G, Carlén M, Meletis K. A whole-brain atlas of inputs to serotonergic neurons of the dorsal and median raphe nuclei. Neuron 2014; 83:663-78. [PMID: 25102561 DOI: 10.1016/j.neuron.2014.07.002] [Citation(s) in RCA: 283] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2014] [Indexed: 01/02/2023]
Abstract
The serotonin system is proposed to regulate physiology and behavior and to underlie mood disorders; nevertheless, the circuitry controlling serotonergic neurons remains uncharacterized. We therefore generated a comprehensive whole-brain atlas defining the monosynaptic inputs onto forebrain-projecting serotonergic neurons of dorsal versus median raphe based on a genetically restricted transsynaptic retrograde tracing strategy. We identified discrete inputs onto serotonergic neurons from forebrain and brainstem neurons, with specific inputs from hypothalamus, cortex, basal ganglia, and midbrain, displaying a greater than anticipated complexity and diversity in cell-type-specific connectivity. We identified and functionally confirmed monosynaptic glutamatergic inputs from prefrontal cortex and lateral habenula onto serotonergic neurons as well as a direct GABAergic input from striatal projection neurons. In summary, our findings emphasize the role of hyperdirect inputs to serotonergic neurons. Cell-type-specific classification of connectivity patterns will allow for further functional analysis of the diverse but specific inputs that control serotonergic neurons during behavior.
Collapse
Affiliation(s)
| | - Daniel Fürth
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Yang Xuan
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Yvonne Johansson
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Laura Pozzi
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Gilad Silberberg
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Marie Carlén
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | | |
Collapse
|
13
|
Tuckwell HC, Penington NJ. Computational modeling of spike generation in serotonergic neurons of the dorsal raphe nucleus. Prog Neurobiol 2014; 118:59-101. [PMID: 24784445 DOI: 10.1016/j.pneurobio.2014.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 04/14/2014] [Accepted: 04/21/2014] [Indexed: 01/14/2023]
Abstract
Serotonergic neurons of the dorsal raphe nucleus, with their extensive innervation of limbic and higher brain regions and interactions with the endocrine system have important modulatory or regulatory effects on many cognitive, emotional and physiological processes. They have been strongly implicated in responses to stress and in the occurrence of major depressive disorder and other psychiatric disorders. In order to quantify some of these effects, detailed mathematical models of the activity of such cells are required which describe their complex neurochemistry and neurophysiology. We consider here a single-compartment model of these neurons which is capable of describing many of the known features of spike generation, particularly the slow rhythmic pacemaking activity often observed in these cells in a variety of species. Included in the model are 11 kinds of ion channels: a fast sodium current INa, a delayed rectifier potassium current IKDR, a transient potassium current IA, a slow non-inactivating potassium current IM, a low-threshold calcium current IT, two high threshold calcium currents IL and IN, small and large conductance potassium currents ISK and IBK, a hyperpolarization-activated cation current IH and a leak current ILeak. In Sections 3-8, each current type is considered in detail and parameters estimated from voltage clamp data where possible. Three kinds of model are considered for the BK current and two for the leak current. Intracellular calcium ion concentration Cai is an additional component and calcium dynamics along with buffering and pumping is discussed in Section 9. The remainder of the article contains descriptions of computed solutions which reveal both spontaneous and driven spiking with several parameter sets. Attention is focused on the properties usually associated with these neurons, particularly long duration of action potential, steep upslope on the leading edge of spikes, pacemaker-like spiking, long-lasting afterhyperpolarization and the ramp-like return to threshold after a spike. In some cases the membrane potential trajectories display doublets or have humps or notches as have been reported in some experimental studies. The computed time courses of IA and IT during the interspike interval support the generally held view of a competition between them in influencing the frequency of spiking. Spontaneous activity was facilitated by the presence of IH which has been found in these neurons by some investigators. For reasonable sets of parameters spike frequencies between about 0.6Hz and 1.2Hz are obtained, but frequencies as high as 6Hz could be obtained with special parameter choices. Topics investigated and compared with experiment include shoulders, notches, anodal break phenomena, the effects of noradrenergic input, frequency versus current curves, depolarization block, effects of cell size and the effects of IM. The inhibitory effects of activating 5-HT1A autoreceptors are also investigated. There is a considerable discussion of in vitro versus in vivo firing behavior, with focus on the roles of noradrenergic input, corticotropin-releasing factor and orexinergic inputs. Location of cells within the nucleus is probably a major factor, along with the state of the animal.
Collapse
Affiliation(s)
- Henry C Tuckwell
- Max Planck Institute for Mathematics in the Sciences, Inselstr. 22, 04103 Leipzig, Germany; School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Nicholas J Penington
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Box 29, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA; Program in Neural and Behavioral Science and Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Medical Center, Box 29, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| |
Collapse
|
14
|
Nakamura K, Wong-Lin K. Functions and computational principles of serotonergic and related systems at multiple scales. Front Integr Neurosci 2014; 8:23. [PMID: 24639632 PMCID: PMC3945473 DOI: 10.3389/fnint.2014.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 02/19/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kae Nakamura
- Department of Physiology, Kansai Medical University Osaka, Japan
| | - Kongfatt Wong-Lin
- Intelligent Systems Research Centre, School of Computing and Intelligent Systems, University of Ulster Northern Ireland, L'Derry, UK
| |
Collapse
|