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Vijatovic D, Toma FA, Harrington ZPM, Sommer C, Hauschild R, Trevisan AJ, Chapman P, Julseth MJ, Brenner-Morton S, Gabitto MI, Dasen JS, Bikoff JB, Sweeney LB. Spinal neuron diversity scales exponentially with swim-to-limb transformation during frog metamorphosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.20.614050. [PMID: 39345366 PMCID: PMC11430061 DOI: 10.1101/2024.09.20.614050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
Vertebrates exhibit a wide range of motor behaviors, ranging from swimming to complex limb-based movements. Here we take advantage of frog metamorphosis, which captures a swim-to-limb-based movement transformation during the development of a single organism, to explore changes in the underlying spinal circuits. We find that the tadpole spinal cord contains small and largely homogeneous populations of motor neurons (MNs) and V1 interneurons (V1s) at early escape swimming stages. These neuronal populations only modestly increase in number and subtype heterogeneity with the emergence of free swimming. In contrast, during frog metamorphosis and the emergence of limb movement, there is a dramatic expansion of MN and V1 interneuron number and transcriptional heterogeneity, culminating in cohorts of neurons that exhibit striking molecular similarity to mammalian motor circuits. CRISPR/Cas9-mediated gene disruption of the limb MN and V1 determinants FoxP1 and Engrailed-1, respectively, results in severe but selective deficits in tail and limb function. Our work thus demonstrates that neural diversity scales exponentially with increasing behavioral complexity and illustrates striking evolutionary conservation in the molecular organization and function of motor circuits across species.
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Affiliation(s)
- David Vijatovic
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | | | | | - Robert Hauschild
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Alexandra J. Trevisan
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Phillip Chapman
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Mara J. Julseth
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Mariano I. Gabitto
- Allen Institute for Brain Science, Seattle, WA, USA
- Department of Statistics, University of Washington, Seattle, WA, 98109, USA
| | - Jeremy S. Dasen
- NYU Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA
| | - Jay B. Bikoff
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Lora B. Sweeney
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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2
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Reinshagen A. Grid cells: the missing link in understanding Parkinson's disease? Front Neurosci 2024; 18:1276714. [PMID: 38389787 PMCID: PMC10881698 DOI: 10.3389/fnins.2024.1276714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 01/24/2024] [Indexed: 02/24/2024] Open
Abstract
The mechanisms underlying Parkinson's disease (PD) are complex and not fully understood, and the box-and-arrow model among other current models present significant challenges. This paper explores the potential role of the allocentric brain and especially its grid cells in several PD motor symptoms, including bradykinesia, kinesia paradoxa, freezing of gait, the bottleneck phenomenon, and their dependency on cueing. It is argued that central hubs, like the locus coeruleus and the pedunculopontine nucleus, often narrowly interpreted in the context of PD, play an equally important role in governing the allocentric brain as the basal ganglia. Consequently, the motor and secondary motor (e.g., spatially related) symptoms of PD linked with dopamine depletion may be more closely tied to erroneous computation by grid cells than to the basal ganglia alone. Because grid cells and their associated central hubs introduce both spatial and temporal information to the brain influencing velocity perception they may cause bradykinesia or hyperkinesia as well. In summary, PD motor symptoms may primarily be an allocentric disturbance resulting from virtual faulty computation by grid cells revealed by dopamine depletion in PD.
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3
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Ryczko D, Dubuc R. Dopamine control of downstream motor centers. Curr Opin Neurobiol 2023; 83:102785. [PMID: 37774481 DOI: 10.1016/j.conb.2023.102785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/18/2023] [Accepted: 08/26/2023] [Indexed: 10/01/2023]
Abstract
The role of dopamine in the control of movement is traditionally associated with ascending projections to the basal ganglia. However, more recently descending dopaminergic pathways projecting to downstream brainstem motor circuits were discovered. In lampreys, salamanders, and rodents, these include projections to the downstream Mesencephalic Locomotor Region (MLR), a brainstem region controlling locomotion. Such descending dopaminergic projections could prime brainstem networks controlling movement. Other descending dopaminergic projections have been shown to reach reticulospinal cells involved in the control of locomotion. In addition, dopamine directly modulates the activity of interneurons and motoneurons. Beyond locomotion, dopaminergic inputs modulate visuomotor transformations within the optic tectum (mammalian superior colliculus). Loss of descending dopaminergic inputs will likely contribute to pathological conditions such as in Parkinson's disease.
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Affiliation(s)
- Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada; Neurosciences Sherbrooke, Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Sherbrooke, Canada.
| | - Réjean Dubuc
- Groupe de Recherche en Activité Physique Adaptée, Département des Sciences de l'Activité Physique, Université du Québec à Montréal, Montréal, Québec, Canada; Groupe de recherche sur la Signalisation Neurale et la Circuiterie, Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.
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4
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Li C, Li Y, Zhang W, Ma Z, Xiao S, Xie W, Miao S, Li B, Lu G, Liu Y, Bai W, Yu S. Dopaminergic Projections from the Hypothalamic A11 Nucleus to the Spinal Trigeminal Nucleus Are Involved in Bidirectional Migraine Modulation. Int J Mol Sci 2023; 24:16876. [PMID: 38069205 PMCID: PMC10706593 DOI: 10.3390/ijms242316876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/24/2023] [Accepted: 11/25/2023] [Indexed: 12/18/2023] Open
Abstract
Clinical imaging studies have revealed that the hypothalamus is activated in migraine patients prior to the onset of and during headache and have also shown that the hypothalamus has increased functional connectivity with the spinal trigeminal nucleus. The dopaminergic system of the hypothalamus plays an important role, and the dopamine-rich A11 nucleus may play an important role in migraine pathogenesis. We used intraperitoneal injections of glyceryl trinitrate to establish a model of acute migraine attack and chronicity in mice, which was verified by photophobia experiments and von Frey experiments. We explored the A11 nucleus and its downstream pathway using immunohistochemical staining and neuronal tracing techniques. During acute migraine attack and chronification, c-fos expression in GABAergic neurons in the A11 nucleus was significantly increased, and inhibition of DA neurons was achieved by binding to GABA A-type receptors on the surface of dopaminergic neurons in the A11 nucleus. However, the expression of tyrosine hydroxylase and glutamic acid decarboxylase proteins in the A11 nucleus of the hypothalamus did not change significantly. Specific destruction of dopaminergic neurons in the A11 nucleus of mice resulted in severe nociceptive sensitization and photophobic behavior. The expression levels of the D1 dopamine receptor and D2 dopamine receptor in the caudal part of the spinal trigeminal nucleus candalis of the chronic migraine model were increased. Skin nociceptive sensitization of mice was slowed by activation of the D2 dopamine receptor in SP5C, and activation of the D1 dopamine receptor reversed this behavioral change. GABAergic neurons in the A11 nucleus were activated and exerted postsynaptic inhibitory effects, which led to a decrease in the amount of DA secreted by the A11 nucleus in the spinal trigeminal nucleus candalis. The reduced DA bound preferentially to the D2 dopamine receptor, thus exerting a defensive effect against headache.
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Affiliation(s)
- Chenhao Li
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- Medical School of Chinese PLA, Beijing 100853, China
| | - Yang Li
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- Medical School of Chinese PLA, Beijing 100853, China
| | - Wenwen Zhang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- School of Medicine, Nankai University, Tianjin 300071, China
| | - Zhenjie Ma
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- Medical School of Chinese PLA, Beijing 100853, China
| | - Shaobo Xiao
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- Medical School of Chinese PLA, Beijing 100853, China
| | - Wei Xie
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
| | - Shuai Miao
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
| | - Bozhi Li
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
| | - Guangshuang Lu
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- Medical School of Chinese PLA, Beijing 100853, China
| | - Yingyuan Liu
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
- Medical School of Chinese PLA, Beijing 100853, China
| | - Wenhao Bai
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
| | - Shengyuan Yu
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, China; (C.L.); (Y.L.); (W.Z.); (Z.M.); (S.X.); (W.X.); (S.M.); (B.L.); (G.L.); (Y.L.); (W.B.)
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5
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Sillar KT, Simmers J, Combes D. From tadpole to adult frog locomotion. Curr Opin Neurobiol 2023; 82:102753. [PMID: 37549591 DOI: 10.1016/j.conb.2023.102753] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/05/2023] [Accepted: 07/05/2023] [Indexed: 08/09/2023]
Abstract
The transition from larval to adult locomotion in the anuran, Xenopus laevis, involves a dramatic switch from axial to appendicular swimming including intermediate stages when the tail and hindlimbs co-exist and contribute to propulsion. Hatchling tadpole swimming is generated by an axial central pattern generator (CPG) which matures rapidly during early larval life. During metamorphosis, the developing limbs are controlled by a de novo appendicular CPG driven initially by the axial system before segregating to allow both systems to operate together or independently. Neuromodulation plays important roles throughout, but key modulators switch their effects from early inhibitory influences to facilitating locomotion. Temperature affects the construction and operation of locomotor networks and global changes in environmental temperature place aquatic poikilotherms, like amphibians, at risk. The locomotor control strategy of anurans differs from other amphibian groups such as salamanders, where evolution has acted upon the thyroid hormone pathway to sculpt different developmental outcomes.
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Affiliation(s)
- Keith T Sillar
- School of Psychology and Neuroscience, University of St Andrews, St Marys Quad., St Andrews, Fife KY16 9AP, Scotland.
| | - John Simmers
- Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, CNRS UMR 5287, Université de Bordeaux, 33706 Bordeaux, France
| | - Denis Combes
- Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, CNRS UMR 5287, Université de Bordeaux, 33706 Bordeaux, France
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6
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Liu GQ, Liu ZX, Lin ZX, Chen P, Yan YC, Lin QR, Hu YJ, Jiang N, Yu B. Effects of Dopamine on stem cells and its potential roles in the treatment of inflammatory disorders: a narrative review. Stem Cell Res Ther 2023; 14:230. [PMID: 37649087 PMCID: PMC10469852 DOI: 10.1186/s13287-023-03454-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 08/16/2023] [Indexed: 09/01/2023] Open
Abstract
Inflammation is the host's protective response against harmful external stimulation that helps tissue repair and remodeling. However, excessive inflammation seriously threatens the patient's life. Due to anti-inflammatory effects, corticosteroids, immunosuppressants, and monoclonal antibodies are used to treat various inflammatory diseases, but drug resistance, non-responsiveness, and severe side effect limit their development and application. Therefore, developing other alternative therapies has become essential in anti-inflammatory therapy. In recent years, the in-depth study of stem cells has made them a promising alternative drug for the treatment of inflammatory diseases, and the function of stem cells is regulated by a variety of signals, of which dopamine signaling is one of the main influencing factors. In this review, we review the effects of dopamine on various adult stem cells (neural stem cells, mesenchymal stromal cells, hematopoietic stem cells, and cancer stem cells) and their signaling pathways, as well as the application of some critical dopamine receptor agonists/antagonists. Besides, we also review the role of various adult stem cells in inflammatory diseases and discuss the potential anti-inflammation function of dopamine receptors, which provides a new therapeutic target for regenerative medicine in inflammatory diseases.
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Affiliation(s)
- Guan-Qiao Liu
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Zi-Xian Liu
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Ze-Xin Lin
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Peng Chen
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Yu-Chi Yan
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Qing-Rong Lin
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Yan-Jun Hu
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China
| | - Nan Jiang
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China.
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China.
| | - Bin Yu
- Division of Orthopaedics & Traumatology, Department of Orthopaedics, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China.
- Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Southern Medical University Nanfang Hospital, Guangzhou, 510515, China.
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7
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Silvani A, Ghorayeb I, Manconi M, Li Y, Clemens S. Putative Animal Models of Restless Legs Syndrome: A Systematic Review and Evaluation of Their Face and Construct Validity. Neurotherapeutics 2023; 20:154-178. [PMID: 36536233 PMCID: PMC10119375 DOI: 10.1007/s13311-022-01334-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Restless legs syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs, which is often accompanied by periodic limb movements during sleep. RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergic agonists that target D2-like receptors, in particular D2 and D3, but the long-term response is often unsatisfactory. Over the years, several putative animal models for RLS have been developed, mainly based on the epidemiological and neurochemical link with iron deficiency, treatment efficacy of D2-like dopaminergic agonists, or genome-wide association studies that identified risk factors in the patient population. Here, we present the first systematic review of putative animal models of RLS, provide information about their face and construct validity, and report their role in deciphering the underlying pathophysiological mechanisms that may cause or contribute to RLS. We propose that identifying the causal links between genetic risk factors, altered organ functions, and changes to molecular pathways in neural circuitry will eventually lead to more effective new treatment options that bypass the side effects of the currently used therapeutics in RLS, especially for long-term therapy.
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Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Ravenna Campus, Ravenna, Italy
| | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, Université de Bordeaux, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, CNRS, Bordeaux, France
| | - Mauro Manconi
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, EOC, Ospedale Civico, Lugano, Switzerland
- Department of Neurology, University Hospital, Inselspital, Bern, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
| | - Yuqing Li
- Department of Neurology, College of Medicine, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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8
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Piña-Leyva C, Lara-Lozano M, Rodríguez-Sánchez M, Vidal-Cantú GC, Barrientos Zavalza E, Jiménez-Estrada I, Delgado-Lezama R, Rodríguez-Sosa L, Granados-Soto V, González-Barrios JA, Florán-Garduño B. Hypothalamic A11 Nuclei Regulate the Circadian Rhythm of Spinal Mechanonociception through Dopamine Receptors and Clock Gene Expression. Life (Basel) 2022; 12:life12091411. [PMID: 36143447 PMCID: PMC9506518 DOI: 10.3390/life12091411] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/26/2022] Open
Abstract
Several types of sensory perception have circadian rhythms. The spinal cord can be considered a center for controlling circadian rhythms by changing clock gene expression. However, to date, it is not known if mechanonociception itself has a circadian rhythm. The hypothalamic A11 area represents the primary source of dopamine (DA) in the spinal cord and has been found to be involved in clock gene expression and circadian rhythmicity. Here, we investigate if the paw withdrawal threshold (PWT) has a circadian rhythm, as well as the role of the dopaminergic A11 nucleus, DA, and DA receptors (DR) in the PWT circadian rhythm and if they modify clock gene expression in the lumbar spinal cord. Naïve rats showed a circadian rhythm of the PWT of almost 24 h, beginning during the night–day interphase and peaking at 14.63 h. Similarly, DA and DOPAC’s spinal contents increased at dusk and reached their maximum contents at noon. The injection of 6-hydroxydopamine (6-OHDA) into the A11 nucleus completely abolished the circadian rhythm of the PWT, reduced DA tissue content in the lumbar spinal cord, and induced tactile allodynia. Likewise, the repeated intrathecal administration of D1-like and D2-like DA receptor antagonists blunted the circadian rhythm of PWT. 6-OHDA reduced the expression of Clock and Per1 and increased Per2 gene expression during the day. In contrast, 6-OHDA diminished Clock, Bmal, Per1, Per2, Per3, Cry1, and Cry2 at night. The repeated intrathecal administration of the D1-like antagonist (SCH-23390) reduced clock genes throughout the day (Clock and Per2) and throughout the night (Clock, Per2 and Cry1), whereas it increased Bmal and Per1 throughout the day. In contrast, the intrathecal injection of the D2 receptor antagonists (L-741,626) increased the clock genes Bmal, Per2, and Per3 and decreased Per1 throughout the day. This study provides evidence that the circadian rhythm of the PWT results from the descending dopaminergic modulation of spinal clock genes induced by the differential activation of spinal DR.
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Affiliation(s)
- Celia Piña-Leyva
- · Department of Physiology, Biophysics, and Neurosciences, CINVESTAV, Av. No. 2508 National Polytechnic Institute, Mexico City 06760, Mexico
| | - Manuel Lara-Lozano
- · Department of Physiology, Biophysics, and Neurosciences, CINVESTAV, Av. No. 2508 National Polytechnic Institute, Mexico City 06760, Mexico
- Genomic Medicine Laboratory, Regional Hospital “October 1st”, ISSSTE, Av. No. 1669 National Polytechnic Institute, Mexico City 07760, Mexico
| | - Marina Rodríguez-Sánchez
- · Department of Physiology, Biophysics, and Neurosciences, CINVESTAV, Av. No. 2508 National Polytechnic Institute, Mexico City 06760, Mexico
| | - Guadalupe C. Vidal-Cantú
- Neurobiology of Pain Laboratory, Departamento de Farmacología, Cinvestav, Sede Sur, México City 14330, Mexico
| | - Ericka Barrientos Zavalza
- Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City 09340, Mexico
| | - Ismael Jiménez-Estrada
- · Department of Physiology, Biophysics, and Neurosciences, CINVESTAV, Av. No. 2508 National Polytechnic Institute, Mexico City 06760, Mexico
| | - Rodolfo Delgado-Lezama
- · Department of Physiology, Biophysics, and Neurosciences, CINVESTAV, Av. No. 2508 National Polytechnic Institute, Mexico City 06760, Mexico
| | - Leonardo Rodríguez-Sosa
- Department of Physiology, Medicine Faculty, National Autonomous University of Mexico, University City, Mexico City 04510, Mexico
| | - Vinicio Granados-Soto
- Neurobiology of Pain Laboratory, Departamento de Farmacología, Cinvestav, Sede Sur, México City 14330, Mexico
| | - Juan Antonio González-Barrios
- Genomic Medicine Laboratory, Regional Hospital “October 1st”, ISSSTE, Av. No. 1669 National Polytechnic Institute, Mexico City 07760, Mexico
- Correspondence: (J.A.G.-B.); (B.F.-G.); Tel.: +52-55-81077971 (J.A.G.-B.); +52-55-13848283 (B.F.-G.)
| | - Benjamín Florán-Garduño
- · Department of Physiology, Biophysics, and Neurosciences, CINVESTAV, Av. No. 2508 National Polytechnic Institute, Mexico City 06760, Mexico
- Correspondence: (J.A.G.-B.); (B.F.-G.); Tel.: +52-55-81077971 (J.A.G.-B.); +52-55-13848283 (B.F.-G.)
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9
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Hosseini P, Mirsadeghi S, Rahmani S, Izadi A, Rezaei M, Ghodsi Z, Rahimi-Movaghar V, Kiani S. Dopamine Receptors Gene Expression Pattern and Locomotor Improvement Differ Between Female and Male Zebrafish During Spinal Cord Auto Repair. Zebrafish 2022; 19:137-147. [PMID: 35905303 DOI: 10.1089/zeb.2021.0081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The dopaminergic system, a spinal cord (SC) motor circuit regulator, is administrated by sexual hormones and evolutionary conserved in all vertebrates. Accordingly, we hypothesized that the dopamine receptor (DAR) expression pattern may be dissimilar in female and male zebrafish SC auto repair. We implemented an uncomplicated method to induce spinal cord injury (SCI) on fully reproductive adult zebrafish, in both genders. SCI was induced using a 28-gauge needle at 9th-10th vertebra without skin incision. Thereupon, lesioned SC was harvested for DAR gene expression analysis; zebrafish were tracked routinely for any improvement in swim distance, speed, and their roaming capabilities/preference. Our findings revealed discrepancies between drd2a, drd2b, drd3, drd4a, and drd4b expression patterns at 1, 7, and 14 days postinjury (DPI) between female and male zebrafish. The receptors were mostly upregulated at 7 DPI in both genders, whereas drd2a and drd2b were mostly maximized in females. Surprisingly, drd3 was measured greater even in intact SC in males. In addition, female zebrafish were able to swim farther distances more accelerated, in multiple directions, by engaging more caudal muscles compared with males, of course with no statistical significance. Indeed, females were able to generate whole-body rotation and move forward using the muscles downstream to the lesion site, whereas the coordinated movement in males was accomplished by rostral muscles. In conclusion, there are differences in DAR gene expression pattern throughout SC autonomous recovery between adult female and male zebrafish, and also, female locomotion seems to ameliorate more rapidly.
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Affiliation(s)
- Parastoo Hosseini
- Department of Cellular and Molecular Biology, University of Science and Culture, Tehran, Iran.,Department of Stem Cell and Developmental Biology, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.,Department of Brain and Cognitive Sciences, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Sara Mirsadeghi
- Department of Stem Cell and Developmental Biology, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.,Department of Brain and Cognitive Sciences, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Saeid Rahmani
- Department of Computer Engineering, Sharif University of Technology, Tehran, Iran
| | - Amin Izadi
- Department of Embryology, Reproductive Biomedicine Research Center, ROYAN Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Mohammad Rezaei
- Department of Stem Cell and Developmental Biology, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Zahra Ghodsi
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Vafa Rahimi-Movaghar
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran.,Department of Neurosurgery, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.,Universal Scientific Education and Research Network (USERN), Tehran, Iran.,Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.,Spine Program, University of Toronto, Toronto, Canada
| | - Sahar Kiani
- Department of Stem Cell and Developmental Biology, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.,Department of Brain and Cognitive Sciences, Cell Science Research Center, ROYAN Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
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10
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Dopamine Suppresses Osteogenic Differentiation of Rat Bone Marrow-Derived Mesenchymal Stem Cells via AKT/GSK-3β/β-Catenin Signaling Pathway. Stem Cells Int 2022; 2022:4154440. [PMID: 35813889 PMCID: PMC9259353 DOI: 10.1155/2022/4154440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 05/12/2022] [Accepted: 06/08/2022] [Indexed: 01/11/2023] Open
Abstract
Nervous system is critically involved in bone homeostasis and osteogenesis. Dopamine, a pivotal neurotransmitter, plays a crucial role in sympathetic regulation, hormone secretion, immune activation, and blood pressure regulation. However, the role of dopamine on osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) remains poorly understood. In this study, we firstly investigated the effect of dopamine on the apoptosis, proliferation, and osteogenic differentiation of rBMSCs. Dopamine did not, however, interfere with the apoptosis and proliferation of rBMSCs. Interestingly, dopamine suppressed the osteogenic differentiation of rBMSCs, as characterized by reduced ALP staining, ALP activity, mineralized nodule formation, and the mRNA and protein levels of osteogenesis-related genes (Col1a1, Alp, Runx2, Opn, and Ocn). Furthermore, dopamine inactivated AKT/GSK-3β/β-catenin signaling pathway. Treatment of LiCl (GSK-3β inhibitor) rescued the inhibitory effects of dopamine on osteogenic differentiation of rBMSCs. LY294002 (AKT inhibitor) administration exacerbated the inhibitory effects of dopamine on osteogenic differentiation of rBMSCs. Taken together, these findings indicate that dopamine suppresses osteogenic differentiation of rBMSCs via AKT/GSK-3β/β-catenin signaling pathway. Our study provides new insights into the role of neurotransmitters in bone homeostasis.
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11
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Sharples SA, Parker J, Vargas A, Milla-Cruz JJ, Lognon AP, Cheng N, Young L, Shonak A, Cymbalyuk GS, Whelan PJ. Contributions of h- and Na+/K+ Pump Currents to the Generation of Episodic and Continuous Rhythmic Activities. Front Cell Neurosci 2022; 15:715427. [PMID: 35185470 PMCID: PMC8855656 DOI: 10.3389/fncel.2021.715427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 12/29/2021] [Indexed: 12/31/2022] Open
Abstract
Developing spinal motor networks produce a diverse array of outputs, including episodic and continuous patterns of rhythmic activity. Variation in excitability state and neuromodulatory tone can facilitate transitions between episodic and continuous rhythms; however, the intrinsic mechanisms that govern these rhythms and their transitions are poorly understood. Here, we tested the capacity of a single central pattern generator (CPG) circuit with tunable properties to generate multiple outputs. To address this, we deployed a computational model composed of an inhibitory half-center oscillator (HCO). Following predictions of our computational model, we tested the contributions of key properties to the generation of an episodic rhythm produced by isolated spinal cords of the newborn mouse. The model recapitulates the diverse state-dependent rhythms evoked by dopamine. In the model, episodic bursting depended predominantly on the endogenous oscillatory properties of neurons, with Na+/K+ ATPase pump (IPump) and hyperpolarization-activated currents (Ih) playing key roles. Modulation of either IPump or Ih produced transitions between episodic and continuous rhythms and silence. As maximal activity of IPump decreased, the interepisode interval and period increased along with a reduction in episode duration. Decreasing maximal conductance of Ih decreased episode duration and increased interepisode interval. Pharmacological manipulations of Ih with ivabradine, and IPump with ouabain or monensin in isolated spinal cords produced findings consistent with the model. Our modeling and experimental results highlight key roles of Ih and IPump in producing episodic rhythms and provide insight into mechanisms that permit a single CPG to produce multiple patterns of rhythmicity.
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Affiliation(s)
- Simon A. Sharples
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Neuroscience, University of Calgary, Calgary, AB, Canada
| | - Jessica Parker
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Alex Vargas
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Jonathan J. Milla-Cruz
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Adam P. Lognon
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Neuroscience, University of Calgary, Calgary, AB, Canada
| | - Ning Cheng
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Leanne Young
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Anchita Shonak
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Neuroscience, University of Calgary, Calgary, AB, Canada
| | - Gennady S. Cymbalyuk
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, United States
- Gennady S. Cymbalyuk,
| | - Patrick J. Whelan
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Neuroscience, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
- *Correspondence: Patrick J. Whelan,
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12
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Abstract
Restless Legs Syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs that is often accompanied by periodic limb movements during sleep (PLMS). RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergics that target the D3 receptor. However, over time patients often develop a gradual tolerance that can lead to the emergence of adverse effects and the augmentation of the symptoms. While the basal ganglia and the striatum control leg movements, the lumbar spinal cord is the gateway for the sensory processing of the symptoms and critical for the associated leg movements. D3 receptors are highly expressed in nucleus accumbens (NAc) of the striatum and the sensory-processing areas of the spinal dorsal horn. In contrast, D1 receptors are strongly expressed throughout the entire striatum and in the ventral horn of the spinal cord. Long-term treatment with D3 receptor full agonists is associated with an upregulation of the D1 receptor subtype, and D3 and D1 receptors can form functional heteromers, in which the D3R controls the D1R function. It is conceivable that the switch from beneficial treatment to augmentation observed in RLS patients after prolonged D3R agonist exposure may be the result of unmasked D1-like receptor actions.
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Affiliation(s)
- Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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13
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Montgomery JE, Wahlstrom‐Helgren S, Vanpelt KT, Masino MA. Repetitive optogenetic stimulation of glutamatergic neurons: An alternative to NMDA treatment for generating locomotor activity in spinalized zebrafish larvae. Physiol Rep 2021; 9:e14774. [PMID: 33769694 PMCID: PMC7995545 DOI: 10.14814/phy2.14774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
N-methyl-d-aspartate (NMDA) application has conventionally been used to activate spinal networks to induce locomotion in spinalized animals. We recently described an alternative approach in which application of continuous blue light activates channelrhodopsin-2 in vesicular glutamate transporter 2a (vglut2a)-expressing spinal neurons to produce organized, rhythmic locomotor activity in spinally-transected larval zebrafish. This technique arguably enhances research validity, because endogenous glutamate is released into existing synapses instead of activating only a subset of glutamatergic (NMDA) receptors with an exogenous compound. Here, we explored the viability of this approach in the context of using it for longer-term experiments. Fictive swimming was induced through repetitive application of 10-s blue light stimuli to spinalized preparations for up to 60 min at intervals of 1, 3, or 15 min. Locomotor activity was maintained throughout the experimental timecourse, demonstrating the robustness of the system. Although locomotor bursts remained organized into episodes of activity, the number of bursts elicited during each successive stimulus decreased. This was in contrast to NMDA bath application, in which bursts became less episodically organized while the overall number of bursts remained unchanged. The efficacy of the repetitive optogenetic stimulation paradigm was demonstrated through application of exogenous dopamine, which reversibly decreased the number of bursts produced per stimulus compared with untreated preparations. Finally, increasing the stimulus interval to 15 min lessened, but did not eliminate locomotor fatigue from repetitive activation. Altogether, we established repetitive optogenetic stimulation of vglut2a-expressing neurons as a viable alternative to NMDA application for activation of the zebrafish spinal locomotor network.
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Affiliation(s)
| | | | - Kayce T. Vanpelt
- Department of NeuroscienceUniversity of MinnesotaMinneapolisMNUSA
| | - Mark A. Masino
- Department of NeuroscienceUniversity of MinnesotaMinneapolisMNUSA
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14
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Differential dopamine modulation of spinal reflex amplitudes is associated with the presence or absence of the autonomic nervous system. Neurosci Lett 2020; 742:135514. [PMID: 33227368 DOI: 10.1016/j.neulet.2020.135514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 11/22/2022]
Abstract
The spinal cord contains a highly collateralized network of descending dopamine (DA) fibers that stem from the dorso-posterior hypothalamic A11 region in the brain, however, the modulatory actions of DA have generally only been assessed in lumbar segments L2-L5. In contrast to these exclusively sensorimotor segments, spinal cords segments T1-L2 and, in mouse, L6-S2, additionally contain the intermediolateral (IML) nucleus, the origin of autonomic nervous system (ANS). Here, we tested if the different spinal circuits in sensorimotor and IML-containing segments react differently to the modulation of the monosynaptic reflex (MSR) by DA. Bath-application of DA (1 μM) led to a decrease of MSR amplitude in L3-L5 segments; however, in IML-containing segments (T10-L2, and S1/2) the MSR response was facilitated. We did not observe any difference in the response between thoracic (sympathetic) and lumbosacral (parasympathetic) segments. Application of the D2-receptor agonists bromocriptine or quinpirole mimicked the effects of DA, while blocking D2 receptor pathways with raclopride or application with the D1-receptor agonist SKF 38393 led to an increase of the MSR in L3-L5 segments and a decrease of the MSR in IML-containing segments. In contrast, in the presence of the gap-junction blockers, carbenoloxone and quinine, DA modulatory actions in IML-containing segments were similar to those of sensorimotor L3-L5 segments. We suggest that DA modulates MSR amplitudes in the spinal cord in a segment-specific manner, and that the differential outcome observed in ANS segments may be a result of gap junctions in the IML.
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15
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Ondo WG, Olubajo T. Exploratory cross-over, trial of augmented RLS with the dopamine receptor 1/5 antagonist ecopipam D1/D5 antagonist ecopipam for augmented RLS. Int J Neurosci 2020; 132:778-782. [PMID: 33066723 DOI: 10.1080/00207454.2020.1838515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Restless legs syndrome (RLS) is a common condition that initially responds dramatically to dopaminergic therapy. Over time, however, dopaminergics cause augmentation, where symptoms occur earlier and intensify. Animal models suggest this may result from increased dopamine receptor type-1 affinity in the spinal cord. Ecopipam is a potent, specific dopamine-1/5 receptor antagonist. METHODS We performed a small (N = 10) exploratory placebo controlled, cross-over safety trial of ecopipam (25-100 mg/day) for patients with augmented RLS currently taking dopamine agonists. RESULTS Ecopipam was well tolerated with sedation being the most common adverse event in drug and placebo. Safety scales and serology data were similar to placebo. The study was not powered to demonstrate efficacy and exploratory efficacy data showed no significant improvement compared to placebo, but RLS diaries, the international RLS rating scale, and clinical global impressions all favored drug. No subject worsened on drug or demonstrated rebound worsening after drug discontinuation. CONCLUSION Ecopipam was safe and well tolerated in this initial study for RLS. Given the lack of alternate options, larger efficacy studies for augmented RLS, and potentially de novo RLS are justified.
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Affiliation(s)
- William G Ondo
- Methodist Neurological Institute, University of Texas, Houston, TX, USA.,Weill Cornell Medical School, New York, NY, USA
| | - Titilayo Olubajo
- Methodist Neurological Institute, University of Texas, Houston, TX, USA
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16
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A dynamic role for dopamine receptors in the control of mammalian spinal networks. Sci Rep 2020; 10:16429. [PMID: 33009442 PMCID: PMC7532218 DOI: 10.1038/s41598-020-73230-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 09/11/2020] [Indexed: 12/21/2022] Open
Abstract
Dopamine is well known to regulate movement through the differential control of direct and indirect pathways in the striatum that express D1 and D2 receptors respectively. The spinal cord also expresses all dopamine receptors; however, how the specific receptors regulate spinal network output in mammals is poorly understood. We explore the receptor-specific mechanisms that underlie dopaminergic control of spinal network output of neonatal mice during changes in spinal network excitability. During spontaneous activity, which is a characteristic of developing spinal networks operating in a low excitability state, we found that dopamine is primarily inhibitory. We uncover an excitatory D1-mediated effect of dopamine on motoneurons and network output that also involves co-activation with D2 receptors. Critically, these excitatory actions require higher concentrations of dopamine; however, analysis of dopamine concentrations of neonates indicates that endogenous levels of spinal dopamine are low. Because endogenous levels of spinal dopamine are low, this excitatory dopaminergic pathway is likely physiologically-silent at this stage in development. In contrast, the inhibitory effect of dopamine, at low physiological concentrations is mediated by parallel activation of D2, D3, D4 and α2 receptors which is reproduced when endogenous dopamine levels are increased by blocking dopamine reuptake and metabolism. We provide evidence in support of dedicated spinal network components that are controlled by excitatory D1 and inhibitory D2 receptors that is reminiscent of the classic dopaminergic indirect and direct pathway within the striatum. These results indicate that network state is an important factor that dictates receptor-specific and therefore dose-dependent control of neuromodulators on spinal network output and advances our understanding of how neuromodulators regulate neural networks under dynamically changing excitability.
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17
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Silva MH. Effects of low‐dose chlorpyrifos on neurobehavior and potential mechanisms: A review of studies in rodents, zebrafish, and
Caenorhabditis elegans. Birth Defects Res 2020; 112:445-479. [DOI: 10.1002/bdr2.1661] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/10/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Marilyn H. Silva
- Retired from a career in regulatory toxicology and risk assessment
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18
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Dopaminergic Modulation of Orofacial Mechanical Hypersensitivity Induced by Infraorbital Nerve Injury. Int J Mol Sci 2020; 21:ijms21061945. [PMID: 32178439 PMCID: PMC7139594 DOI: 10.3390/ijms21061945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 01/13/2023] Open
Abstract
While the descending dopaminergic control system is not fully understood, it is reported that the hypothalamic A11 nucleus is its principle source. To better understand the impact of this system, particularly the A11 nucleus, on neuropathic pain, we created a chronic constriction injury model of the infraorbital nerve (ION-CCI) in rats. ION-CCI rats received intraperitoneal administrations of quinpirole (a dopamine D2 receptor agonist). ION-CCI rats received microinjections of quinpirole, muscimol [a gamma-aminobutyric acid type A (GABAA) receptor agonist], or neurotoxin 6-hydroxydopamine (6-OHDA) into the A11 nucleus. A von Frey filament was used as a mechanical stimulus on the maxillary whisker pad skin; behavioral and immunohistochemical responses to the stimulation were assessed. After intraperitoneal administration of quinpirole and microinjection of quinpirole or muscimol, ION-CCI rats showed an increase in head-withdrawal thresholds and a decrease in the number of phosphorylated extracellular signal-regulated kinase (pERK) immunoreactive (pERK-IR) cells in the superficial layers of the trigeminal spinal subnucleus caudalis (Vc). Following 6-OHDA microinjection, ION-CCI rats showed a decrease in head-withdrawal thresholds and an increase in the number of pERK-IR cells in the Vc. Our findings suggest the descending dopaminergic control system is involved in the modulation of trigeminal neuropathic pain.
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19
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Abstract
A new study provides evidence in zebrafish that dopamine increases the activity of motor neurons in the spinal cord, and this translates into faster swimming bouts in response to visual stimulation.
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Affiliation(s)
- Cornelis Immanuel van der Zouwen
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada; Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Institut de Pharmacologie de Sherbrooke, Sherbrooke, QC, Canada.
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20
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Jha U, Thirumalai V. Neuromodulatory Selection of Motor Neuron Recruitment Patterns in a Visuomotor Behavior Increases Speed. Curr Biol 2020; 30:788-801.e3. [PMID: 32084402 DOI: 10.1016/j.cub.2019.12.064] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 11/18/2019] [Accepted: 12/19/2019] [Indexed: 01/26/2023]
Abstract
Animals generate locomotion at different speeds to suit their behavioral needs. Spinal circuits generate locomotion at these varying speeds by sequential activation of different spinal interneurons and motor neurons. Larval zebrafish can generate slow swims for prey capture and exploration by activation of secondary motor neurons and much faster and vigorous swims during escape and struggle via additional activation of primary motor neurons. Neuromodulators are known to alter the motor output of spinal circuits, but their precise role in speed regulation is not well understood. Here, in the context of optomotor response (OMR), an innate evoked locomotor behavior, we show that dopamine (DA) provides an additional layer to regulation of swim speed in larval zebrafish. Activation of D1-like receptors increases swim speed during OMR in free-swimming larvae. By analyzing tail bend kinematics in head-restrained larvae, we show that the increase in speed is actuated by larger tail bends. Whole-cell patch-clamp recordings from motor neurons reveal that, during OMR, typically only secondary motor neurons are active, whereas primary motor neurons are quiescent. Activation of D1-like receptors increases intrinsic excitability and excitatory synaptic drive in primary and secondary motor neurons. These actions result in greater recruitment of motor neurons during OMR. Our findings provide an example of neuromodulatory reconfiguration of spinal motor neuron speed modules where members are selectively recruited and motor drive is increased to effect changes in locomotor speed. VIDEO ABSTRACT.
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Affiliation(s)
- Urvashi Jha
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India; SASTRA Deemed University, School of Chemical and Biotechnology, Thanjavur, Tamil Nadu 613401, India
| | - Vatsala Thirumalai
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India.
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21
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van Reij RR, Joosten EA, van den Hoogen NJ. Dopaminergic neurotransmission and genetic variation in chronification of post-surgical pain. Br J Anaesth 2019; 123:853-864. [DOI: 10.1016/j.bja.2019.07.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/10/2019] [Accepted: 07/26/2019] [Indexed: 01/30/2023] Open
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22
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Hachoumi L, Sillar KT. Developmental stage-dependent switching in the neuromodulation of vertebrate locomotor central pattern generator networks. Dev Neurobiol 2019; 80:42-57. [PMID: 31705739 DOI: 10.1002/dneu.22725] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/24/2019] [Accepted: 11/05/2019] [Indexed: 12/27/2022]
Abstract
Neuromodulation plays important and stage-dependent roles in regulating locomotor central pattern (CPG) outputs during vertebrate motor system development. Dopamine, serotonin and nitric oxide are three neuromodulators that potently influence CPG outputs in the development of Xenopus frog tadpole locomotion. However, their roles switch from predominantly inhibitory early in development to mainly excitatory at later stages. In this review, we compare the stage-dependent switching in neuromodulation in Xenopus with other vertebrate systems, notably the mouse and the zebrafish, and highlight features that appear to be phylogenetically conserved.
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Affiliation(s)
- Lamia Hachoumi
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
| | - Keith T Sillar
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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23
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Dopamine receptor D2, but not D1, mediates descending dopaminergic pathway-produced analgesic effect in a trigeminal neuropathic pain mouse model. Pain 2019; 160:334-344. [PMID: 30325872 DOI: 10.1097/j.pain.0000000000001414] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neuropathic pain represents a challenge to clinicians because it is resistant to commonly prescribed analgesics due to its largely unknown mechanisms. Here, we investigated a descending dopaminergic pathway-mediated modulation of trigeminal neuropathic pain. We performed chronic constriction injury of the infraorbital nerve from the maxillary branch of trigeminal nerve to induce trigeminal neuropathic pain in mice. Our retrograde tracing showed that the descending dopaminergic projection from hypothalamic A11 nucleus to spinal trigeminal nucleus caudalis is bilateral. Optogenetic/chemogenetic manipulation of dopamine receptors D1 and D2 in the spinal trigeminal nucleus caudalis produced opposite effects on the nerve injury-induced trigeminal neuropathic pain. Specific excitation of dopaminergic neurons in the A11 nucleus attenuated the trigeminal neuropathic pain through the activation of D2 receptors in the spinal trigeminal nucleus caudalis. Conversely, specific ablation of the A11 dopaminergic neurons exacerbated such pain. Our results suggest that the descending A11-spinal trigeminal nucleus caudalis dopaminergic projection is critical for the modulation of trigeminal neuropathic pain and could be manipulated to treat such pain.
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24
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D3 and D1 receptors: The Yin and Yang in the treatment of restless legs syndrome with dopaminergics. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:79-100. [PMID: 31229178 DOI: 10.1016/bs.apha.2019.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Dopaminergic treatments targeting the D3 receptor subtype to reduce the symptoms of RLS show substantial initial clinical benefits but fail to maintain their efficacy over time. Sensorimotor circuits in the spinal cord are the gateway for the sensory processing of the symptoms and critical for the associated leg movements that relieve the symptoms and the periodic limb movements that often develop during sleep. There is a high preponderance of the inhibitory D3 receptor in the sensory-processing areas of the spinal cord (dorsal horn), whereas the motor areas in the ventral horn more strongly express the excitatory D1 receptor subtype. D3 and D1 receptors can form functional heteromeric ensembles that influence each other. In the spinal cord, long-term treatment with D3 receptor agonists is associated with the upregulation of the D1 receptor subtype and block of D1 receptor function at this stage can restore the D3 receptor effect. Alternate scenarios for a role of dopamine involve a role for the D5 receptor in regulating motor excitability and for the D4 receptor subtype in controlling D3-like effects. A model emerges that proposes that the behavioral changes in RLS, while responsive to D3 receptor agonists, may be ultimately be the result of unmasked increased D1-like receptor activities.
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26
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27
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Cortés A, Casadó-Anguera V, Moreno E, Casadó V. The heterotetrameric structure of the adenosine A 1-dopamine D 1 receptor complex: Pharmacological implication for restless legs syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:37-78. [PMID: 31229177 DOI: 10.1016/bs.apha.2019.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Dopaminergic and purinergic signaling play a pivotal role in neurological diseases associated with motor symptoms, including Parkinson's disease (PD), multiple sclerosis, amyotrophic lateral sclerosis, Huntington disease, Restless Legs Syndrome (RLS), spinal cord injury (SCI), and ataxias. Extracellular dopamine and adenosine exert their functions interacting with specific dopamine (DR) or adenosine (AR) receptors, respectively, expressed on the surface of target cells. These receptors are members of the family A of G protein-coupled receptors (GPCRs), which is the largest protein superfamily in mammalian genomes. GPCRs are target of about 40% of all current marketed drugs, highlighting their importance in clinical medicine. The striatum receives the densest dopamine innervations and contains the highest density of dopamine receptors. The modulatory role of adenosine on dopaminergic transmission depends largely on the existence of antagonistic interactions mediated by specific subtypes of DRs and ARs, the so-called A2AR-D2R and A1R-D1R interactions. Due to the dopamine/adenosine antagonism in the CNS, it was proposed that ARs and DRs could form heteromers in the neuronal cell surface. Therefore, adenosine can affect dopaminergic signaling through receptor-receptor interactions and by modulations in their shared intracellular pathways in the striatum and spinal cord. In this work we describe the allosteric modulations between GPCR protomers, focusing in those of adenosine and dopamine within the A1R-D1R heteromeric complex, which is involved in RLS. We also propose that the knowledge about the intricate allosteric interactions within the A1R-D1R heterotetramer, may facilitate the treatment of motor alterations, not only when the dopamine pathway is hyperactivated (RLS, chorea, etc.) but also when motor function is decreased (SCI, aging, PD, etc.).
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Affiliation(s)
- Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Verònica Casadó-Anguera
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Estefanía Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.
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Casoni F, Galbiati A, Ferini-Strambi L. D3 receptor agonist efficacy in restless legs syndrome. PHARMACOLOGY OF RESTLESS LEGS SYNDROME (RLS) 2019; 84:21-35. [DOI: 10.1016/bs.apha.2019.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Ferré S, Díaz-Ríos M, Salamone JD, Prediger RD. New Developments on the Adenosine Mechanisms of the Central Effects of Caffeine and Their Implications for Neuropsychiatric Disorders. J Caffeine Adenosine Res 2018; 8:121-131. [PMID: 30596206 PMCID: PMC6306650 DOI: 10.1089/caff.2018.0017] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Recent studies on interactions between striatal adenosine and dopamine and one of its main targets, the adenosine A2A receptor–dopamine D2 receptor (A2AR–D2R) heteromer, have provided a better understanding of the mechanisms involved in the psychostimulant effects of caffeine and have brought forward new data on the mechanisms of operation of classical orthosteric ligands within G protein-coupled receptor heteromers. The striatal A2AR–D2R heteromer has a tetrameric structure and forms part of a signaling complex that includes a Gs and a Gi protein and the effector adenyl cyclase (subtype AC5). Another target of caffeine, the adenosine A1 receptor–dopamine D1 receptor (A1R–D1R) heteromer, seems to have a very similar structure. Initially suggested to be localized in the striatum, the A1R–D1R heteromer has now been identified in the spinal motoneuron and shown to mediate the spinally generated caffeine-induced locomotion. In this study, we review the recently discovered properties of A2AR–D2R and A1R–D1R heteromers. Our studies demonstrate that these complexes are a necessary condition to sustain the canonical antagonistic interaction between a Gs-coupled receptor (A2AR or D1R) and a Gi-coupled receptor (D2R or A1R) at the adenylyl cyclase level, which constitutes a new concept in the field of G protein-coupled receptor physiology and pharmacology. A2AR antagonists targeting the striatal A2AR–D2R heteromer are already being considered as therapeutic agents in Parkinson's disease. In this study, we review the preclinical evidence that indicates that caffeine and A2AR antagonists could be used to treat the motivational symptoms of depression and attention-deficit/hyperactivity disorder, while A1R antagonists selectively targeting the spinal A1R–D1R heteromer could be used in the recovery of spinal cord injury.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland
| | - Manuel Díaz-Ríos
- Department of Anatomy and Neurobiology, Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - John D Salamone
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
| | - Rui Daniel Prediger
- Department of Pharmacology, Federal University of Santa Catarina, Florianópolis, Brazil
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30
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Koblinger K, Jean-Xavier C, Sharma S, Füzesi T, Young L, Eaton SEA, Kwok CHT, Bains JS, Whelan PJ. Optogenetic Activation of A11 Region Increases Motor Activity. Front Neural Circuits 2018; 12:86. [PMID: 30364230 PMCID: PMC6193508 DOI: 10.3389/fncir.2018.00086] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/21/2018] [Indexed: 11/13/2022] Open
Abstract
Limbic brain regions drive goal-directed behaviors. These behaviors often require dynamic motor responses, but the functional connectome of limbic structures in the diencephalon that control locomotion is not well known. The A11 region, within the posterior diencephalon has been postulated to contribute to motor function and control of pain. Here we show that the A11 region initiates movement. Photostimulation of channelrhodopsin 2 (ChR2) transfected neurons in A11 slice preparations showed that neurons could follow stimulation at frequencies of 20 Hz. Our data show that photostimulation of ChR2 transfected neurons in the A11 region enhances motor activity often leading to locomotion. Using vGluT2-reporter and vGAT-reporter mice we show that the A11 tyrosine hydroxylase positive (TH) dopaminergic neurons are vGluT2 and vGAT negative. We find that in addition to dopaminergic neurons within the A11 region, there is another neuronal subtype which expresses the monoenzymatic aromatic L-amino acid decarboxylase (AADC), but not TH, a key enzyme involved in the synthesis of catecholamines including dopamine. This monoaminergic-based motor circuit may be involved in the control of motor behavior as part of a broader diencephalic motor region.
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Affiliation(s)
- Kathrin Koblinger
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Céline Jean-Xavier
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Sandeep Sharma
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Tamás Füzesi
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Leanne Young
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Shane E A Eaton
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Charlie Hong Ting Kwok
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Jaideep Singh Bains
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Patrick J Whelan
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
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31
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Comorbidities, treatment, and pathophysiology in restless legs syndrome. Lancet Neurol 2018; 17:994-1005. [PMID: 30244828 DOI: 10.1016/s1474-4422(18)30311-9] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 07/05/2018] [Accepted: 08/08/2018] [Indexed: 12/11/2022]
Abstract
Restless legs syndrome, also known as Willis-Ekbom disease, is a common neurological condition whose manifestation is affected by complex environmental and genetic interactions. Restless legs syndrome can occur on its own, mostly at a young age, or with comorbidities such as cardiovascular disease, diabetes, and arterial hypertension, making it a difficult condition to properly diagnose. However, the concept of restless legs syndrome as being two entities, primary or secondary to another condition, has been challenged with genetic data providing further insight into the pathophysiology of the condition. Although dopaminergic treatment was formerly the first-line therapy, prolonged use can result in a serious worsening of symptoms known as augmentation. Clinical studies on pregabalin, gabapentin enacarbil, oxycodone-naloxone, and iron preparations have provided new treatment options, but most patients still report inadequate long-term management of symptoms. Studies of the hypoxic pathway activation and iron deficiency have provided valuable information about the pathophysiology of restless legs syndrome that should now be translated into new, more effective treatments for restless legs syndrome.
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Meneely S, Dinkins ML, Kassai M, Lyu S, Liu Y, Lin CT, Brewer K, Li Y, Clemens S. Differential Dopamine D1 and D3 Receptor Modulation and Expression in the Spinal Cord of Two Mouse Models of Restless Legs Syndrome. Front Behav Neurosci 2018; 12:199. [PMID: 30233336 PMCID: PMC6131574 DOI: 10.3389/fnbeh.2018.00199] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 08/13/2018] [Indexed: 12/22/2022] Open
Abstract
Restless Legs Syndrome (RLS) is often and successfully treated with dopamine receptor agonists that target the inhibitory D3 receptor subtype, however there is no clinical evidence of a D3 receptor dysfunction in RLS patients. In contrast, genome-wide association studies in RLS patients have established that a mutation of the MEIS1 gene is associated with an increased risk in developing RLS, but the effect of MEIS1 dysfunction on sensorimotor function remain unknown. Mouse models for a dysfunctional D3 receptor (D3KO) and Meis1 (Meis1KO) were developed independently, and each animal expresses some features associated with RLS in the clinic, but they have not been compared in their responsiveness to treatment options used in the clinic. We here confirm that D3KO and Meis1KO animals show increased locomotor activities, but that only D3KO show an increased sensory excitability to thermal stimuli. Next we compared the effects of dopaminergics and opioids in both animal models, and we assessed D1 and D3 dopamine receptor expression in the spinal cord, the gateway for sensorimotor processing. We found that Meis1KO share most of the tested behavioral properties with their wild type (WT) controls, including the modulation of the thermal pain withdrawal reflex by morphine, L-DOPA and D3 receptor (D3R) agonists and antagonists. However, Meis1KO and D3KO were behaviorally more similar to each other than to WT when tested with D1 receptor (D1R) agonists and antagonists. Subsequent Western blot analyses of D1R and D3R protein expression in the spinal cord revealed a significant increase in D1R but not D3R expression in Meis1KO and D3KO over WT controls. As the D3R is mostly present in the dorsal spinal cord where it has been shown to modulate sensory pathways, while activation of the D1Rs can activate motoneurons in the ventral spinal cord, we speculate that D3KO and Meis1KO represent two complementary animal models for RLS, in which the mechanisms of sensory (D3R-mediated) and motor (D1R-mediated) dysfunctions can be differentially explored.
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Affiliation(s)
- Samantha Meneely
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Mai-Lynne Dinkins
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Miki Kassai
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Shangru Lyu
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Yuning Liu
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Chien-Te Lin
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Kori Brewer
- Department of Emergency Medicine, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Yuqing Li
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
- Wuxi Medical School, Jiangnan University, Wuxi, China
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
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Rivera-Oliver M, Moreno E, Álvarez-Bagnarol Y, Ayala-Santiago C, Cruz-Reyes N, Molina-Castro GC, Clemens S, Canela EI, Ferré S, Casadó V, Díaz-Ríos M. Adenosine A 1-Dopamine D 1 Receptor Heteromers Control the Excitability of the Spinal Motoneuron. Mol Neurobiol 2018; 56:797-811. [PMID: 29797183 DOI: 10.1007/s12035-018-1120-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/11/2018] [Indexed: 10/16/2022]
Abstract
While the role of the ascending dopaminergic system in brain function and dysfunction has been a subject of extensive research, the role of the descending dopaminergic system in spinal cord function and dysfunction is just beginning to be understood. Adenosine plays a key role in the inhibitory control of the ascending dopaminergic system, largely dependent on functional complexes of specific subtypes of adenosine and dopamine receptors. Combining a selective destabilizing peptide strategy with a proximity ligation assay and patch-clamp electrophysiology in slices from male mouse lumbar spinal cord, the present study demonstrates the existence of adenosine A1-dopamine D1 receptor heteromers in the spinal motoneuron by which adenosine tonically inhibits D1 receptor-mediated signaling. A1-D1 receptor heteromers play a significant control of the motoneuron excitability, represent main targets for the excitatory effects of caffeine in the spinal cord and can constitute new targets for the pharmacological therapy after spinal cord injury, motor aging-associated disorders and restless legs syndrome.
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Affiliation(s)
- Marla Rivera-Oliver
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Estefanía Moreno
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Yocasta Álvarez-Bagnarol
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Christian Ayala-Santiago
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Nicole Cruz-Reyes
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Gian Carlo Molina-Castro
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Enric I Canela
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Sergi Ferré
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Technology Building, 333 Cassell Drive, Baltimore, MD, 21224, USA.
| | - Vicent Casadó
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Manuel Díaz-Ríos
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
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34
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Acton D, Broadhead MJ, Miles GB. Modulation of spinal motor networks by astrocyte-derived adenosine is dependent on D 1-like dopamine receptor signaling. J Neurophysiol 2018; 120:998-1009. [PMID: 29790837 PMCID: PMC6171060 DOI: 10.1152/jn.00783.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Astrocytes modulate many neuronal networks, including spinal networks responsible for the generation of locomotor behavior. Astrocytic modulation of spinal motor circuits involves release of ATP from astrocytes, hydrolysis of ATP to adenosine, and subsequent activation of neuronal A1 adenosine receptors (A1Rs). The net effect of this pathway is a reduction in the frequency of locomotor-related activity. Recently, it was proposed that A1Rs modulate burst frequency by blocking the D1-like dopamine receptor (D1LR) signaling pathway; however, adenosine also modulates ventral horn circuits by dopamine-independent pathways. Here, we demonstrate that adenosine produced upon astrocytic stimulation modulates locomotor-related activity by counteracting the excitatory effects of D1LR signaling and does not act by previously described dopamine-independent pathways. In spinal cord preparations from postnatal mice, a D1LR agonist, SKF 38393, increased the frequency of locomotor-related bursting induced by 5-hydroxytryptamine and N-methyl-d-aspartate. Bath-applied adenosine reduced burst frequency only in the presence of SKF 38393, as did adenosine produced after activation of protease-activated receptor-1 to stimulate astrocytes. Furthermore, the A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine enhanced burst frequency only in the presence of SKF 38393, indicating that endogenous adenosine produced by astrocytes during network activity also acts by modulating D1LR signaling. Finally, modulation of bursting by adenosine released upon stimulation of astrocytes was blocked by protein kinase inhibitor-(14-22) amide, a protein kinase A (PKA) inhibitor, consistent with A1R-mediated antagonism of the D1LR/adenylyl cyclase/PKA pathway. Together, these findings support a novel, astrocytic mechanism of metamodulation within the mammalian spinal cord, highlighting the complexity of the molecular interactions that specify motor output. NEW & NOTEWORTHY Astrocytes within the spinal cord produce adenosine during ongoing locomotor-related activity or when experimentally stimulated. Here, we show that adenosine derived from astrocytes acts at A1 receptors to inhibit a pathway by which D1-like receptors enhance the frequency of locomotor-related bursting. These data support a novel form of metamodulation within the mammalian spinal cord, enhancing our understanding of neuron-astrocyte interactions and their importance in shaping network activity.
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Affiliation(s)
- David Acton
- School of Psychology and Neuroscience, University of St Andrews , St Andrews , United Kingdom
| | - Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews , St Andrews , United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews , St Andrews , United Kingdom
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35
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Onaolapo AY, Abdusalam SZ, Onaolapo OJ. Silymarin attenuates aspartame-induced variation in mouse behaviour, cerebrocortical morphology and oxidative stress markers. PATHOPHYSIOLOGY 2017; 24:51-62. [DOI: 10.1016/j.pathophys.2017.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/30/2016] [Accepted: 01/16/2017] [Indexed: 12/11/2022] Open
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Loss of the Habenula Intrinsic Neuromodulator Kisspeptin1 Affects Learning in Larval Zebrafish. eNeuro 2017; 4:eN-NWR-0326-16. [PMID: 28534042 PMCID: PMC5437413 DOI: 10.1523/eneuro.0326-16.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/14/2017] [Accepted: 03/30/2017] [Indexed: 12/19/2022] Open
Abstract
Learning how to actively avoid a predictable threat involves two steps: recognizing the cue that predicts upcoming punishment and learning a behavioral response that will lead to avoidance. In zebrafish, ventral habenula (vHb) neurons have been proposed to participate in both steps by encoding the expected aversiveness of a stimulus. vHb neurons increase their firing rate as expectation of punishment grows but reduce their activity as avoidance learning occurs. This leads to changes in the activity of raphe neurons, which are downstream of the vHb, during learning. How vHb activity is regulated is not known. Here, we ask whether the neuromodulator Kisspeptin1, which is expressed in the ventral habenula together with its receptor, could be involved. Kiss1 mutants were generated with CRISPR/Cas9 using guide RNAs targeted to the signal sequence. Mutants, which have a stop codon upstream of the active Kisspeptin1 peptide, have a deficiency in learning to avoid a shock that is predicted by light. Electrophysiology indicates that Kisspeptin1 has a concentration-dependent effect on vHb neurons: depolarizing at low concentrations and hyperpolarizing at high concentrations. Two-photon calcium imaging shows that mutants have reduced raphe response to shock. These data are consistent with the hypothesis that Kisspeptin1 modulates habenula neurons as the fish learns to cope with a threat. Learning a behavioral strategy to overcome a stressor may thus be accompanied by physiological change in the habenula, mediated by intrinsic neuromodulation.
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Samir S, Yllanes AP, Lallemand P, Brewer KL, Clemens S. Morphine responsiveness to thermal pain stimuli is aging-associated and mediated by dopamine D1 and D3 receptor interactions. Neuroscience 2017; 349:87-97. [PMID: 28257894 DOI: 10.1016/j.neuroscience.2017.02.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 01/16/2017] [Accepted: 02/20/2017] [Indexed: 01/09/2023]
Abstract
Morphine actions involve the dopamine (DA) D1 and D3 receptor systems (D1R and D3R), and the responses to morphine change with age. We here explored in differently aged wild-type (WT) and D3R knockout mice (D3KO) the interactions of the D1R/D3R systems with morphine in vivo at three different times of the animals' lifespan (2months, 1year, and 2years). We found that: (1) thermal pain withdrawal reflexes follow an aging-associated phenotype, with relatively longer latencies at 2months and shorter latencies at 1year, (2) over the same age range, a dysfunction of the D3R subtype decreases reflex latencies more than aging alone, (3) morphine altered reflex responses in a dose-dependent manner in WT animals and changed at its higher dose the phenotype of the D3KO animals from a morphine-resistant state to a morphine-responsive state, (4) block of D1R function had an aging-dependent effect on thermal withdrawal latencies in control animals that, in old animals, was stronger than that of low-dose morphine. Lastly, (5) block of D1R function in young D3KO animals mimicked the behavioral phenotype observed in the aged WT. Our proof-of-concept data from the rodent animal model suggest that, with age, block of D1R function may be considered as an alternative to the use of morphine, to modulate the response to painful stimuli.
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Affiliation(s)
- Sophia Samir
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Alexander P Yllanes
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Perrine Lallemand
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Kori L Brewer
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States.
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Smith AN, Kabelik D. The effects of dopamine receptor 1 and 2 agonists and antagonists on sexual and aggressive behaviors in male green anoles. PLoS One 2017; 12:e0172041. [PMID: 28187160 PMCID: PMC5302375 DOI: 10.1371/journal.pone.0172041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/30/2017] [Indexed: 11/29/2022] Open
Abstract
The propensity to exhibit social behaviors during interactions with same-sex and opposite-sex conspecifics is modulated by various neurotransmitters, including dopamine. Dopamine is a conserved neurotransmitter among vertebrates and dopaminergic receptors are also highly conserved among taxa. Activation of D1 and D2 dopamine receptor subtypes has been shown to modulate social behaviors, especially in mammalian and avian studies. However, the specific behavioral functions of these receptors vary across taxa. In reptiles there have been few studies examining the relationship between dopaminergic receptors and social behaviors. We therefore examined the effects of D1 and D2 agonists and antagonists on sexual and aggressive behaviors in the male green anole lizard (Anolis carolinensis). Treatment with high doses of both D1 and D2 agonists was found to impair both sexual and aggressive behaviors. However, the D1 agonist treatment was also found to impair motor function, suggesting that those effects were likely nonspecific. Lower doses of both agonists and antagonists failed to affect social behaviors. These findings provide some evidence for D2 receptor regulation of social behaviors, but in contrast with previous research, these effects are all inhibitory and no effects were found for manipulations of D1 receptors. A potential reason for the lack of more widespread effects on social behaviors using moderate or low drug doses is that systemic injection of drugs resulted in effects throughout the whole brain, thus affecting counteracting circuits which negated one another, making measurable changes in behavioral output difficult to detect. Future studies should administer drugs directly into brain regions known to regulate sexual and aggressive behaviors.
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Affiliation(s)
- Alexandra N. Smith
- Department of Biology, Rhodes College, Memphis, Tennessee, United States of America
- Program in Neuroscience, Rhodes College, Memphis, Tennessee, United States of America
| | - David Kabelik
- Department of Biology, Rhodes College, Memphis, Tennessee, United States of America
- Program in Neuroscience, Rhodes College, Memphis, Tennessee, United States of America
- * E-mail:
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39
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Modulation of Rhythmic Activity in Mammalian Spinal Networks Is Dependent on Excitability State. eNeuro 2017; 4:eN-NWR-0368-16. [PMID: 28144626 PMCID: PMC5272924 DOI: 10.1523/eneuro.0368-16.2017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/21/2022] Open
Abstract
Neuromodulators play an important role in activating rhythmically active motor networks; however, what remains unclear are the network interactions whereby neuromodulators recruit spinal motor networks to produce rhythmic activity. Evidence from invertebrate systems has demonstrated that the effect of neuromodulators depends on the pre-existing state of the network. We explored how network excitation state affects the ability of dopamine to evoke rhythmic locomotor activity in the neonatal mouse isolated spinal cord. We found that dopamine can evoke unique patterns of motor activity that are dependent on the excitability state of motor networks. Different patterns of motor activity ranging from tonic, nonrhythmic activity to multirhythmic, nonlocomotor activity to locomotor activity were produced by altering global motor network excitability through manipulations of the extracellular potassium and bath NMDA concentration. A similar effect was observed when network excitation was manipulated during an unstable multirhythm evoked by a low concentration (15 µm) of 5-HT, suggesting that our results are not neuromodulator specific. Our data show in vertebrate systems that modulation is a two-way street and that modulatory actions are largely influenced by the network state. The level of network excitation can account for variability between preparations and is an additional factor to be considered when circuit elements are removed from the network.
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Onaolapo OJ, Adekola MA, Azeez TO, Salami K, Onaolapo AY. l-Methionine and silymarin: A comparison of prophylactic protective capabilities in acetaminophen-induced injuries of the liver, kidney and cerebral cortex. Biomed Pharmacother 2017; 85:323-333. [DOI: 10.1016/j.biopha.2016.11.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 11/04/2016] [Accepted: 11/08/2016] [Indexed: 02/07/2023] Open
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41
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Picton LD, Sillar KT. Mechanisms underlying the endogenous dopaminergic inhibition of spinal locomotor circuit function in Xenopus tadpoles. Sci Rep 2016; 6:35749. [PMID: 27760989 PMCID: PMC5071771 DOI: 10.1038/srep35749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/30/2016] [Indexed: 01/08/2023] Open
Abstract
Dopamine plays important roles in the development and modulation of motor control circuits. Here we show that dopamine exerts potent effects on the central pattern generator circuit controlling locomotory swimming in post-embryonic Xenopus tadpoles. Dopamine (0.5–100 μM) reduced fictive swim bout occurrence and caused both spontaneous and evoked episodes to become shorter, slower and weaker. The D2-like receptor agonist quinpirole mimicked this repertoire of inhibitory effects on swimming, whilst the D4 receptor antagonist, L745,870, had the opposite effects. The dopamine reuptake inhibitor bupropion potently inhibited fictive swimming, demonstrating that dopamine constitutes an endogenous modulatory system. Both dopamine and quinpirole also inhibited swimming in spinalised preparations, suggesting spinally located dopamine receptors. Dopamine and quinpirole hyperpolarised identified rhythmically active spinal neurons, increased rheobase and reduced spike probability both during swimming and in response to current injection. The hyperpolarisation was TTX-resistant and was accompanied by decreased input resistance, suggesting that dopamine opens a K+ channel. The K+ channel blocker barium chloride (but not TEA, glybenclamide or tertiapin-Q) significantly occluded the hyperpolarisation. Overall, we show that endogenously released dopamine acts upon spinally located D2-like receptors, leading to a rapid inhibitory modulation of swimming via the opening of a K+ channel.
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Affiliation(s)
- Laurence D Picton
- School of Psychology and Neuroscience, University of St Andrews, St Andrews KY16 9JP, United Kingdom
| | - Keith T Sillar
- School of Psychology and Neuroscience, University of St Andrews, St Andrews KY16 9JP, United Kingdom
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42
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Onaolapo AY, Onaolapo OJ, Nwoha PU. Alterations in behaviour, cerebral cortical morphology and cerebral oxidative stress markers following aspartame ingestion. J Chem Neuroanat 2016; 78:42-56. [PMID: 27565676 DOI: 10.1016/j.jchemneu.2016.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/21/2016] [Accepted: 08/22/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The study evaluated changes in open field behaviours, cerebral cortical histomorphology and biochemical markers of oxidative stress following repeated administration of aspartame in mice. METHODOLOGY Adult mice were assigned into five groups of twelve each. Vehicle (distilled water), or aspartame (20, 40, 80 and 160mg/kg body weight) were administered orally for 28days. Horizontal locomotion, rearing and grooming were assessed after the first and last dose of aspartame. Sections of the cerebral cortex were processed and stained for general histology, and also examined for neuritic plaques using the Bielschwosky's protocol. Glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) immunoreactivity were assessed using appropriate antibodies. Aspartate and antioxidant levels were also assayed from cerebral cortex homogenates. Data obtained were analysed using descriptive and inferential statistics. RESULTS Body weight and food consumption decreased significantly with aspartame consumption. Locomotion, rearing and grooming increased significantly after first dose, and with repeated administration of aspartame. Histological changes consistent with neuronal damage were seen at 40, 80 and 160mg/kg. Neuritic plaque formation was not evident; while GFAP-reactive astrocytes and NSE-reactive neurons increased at 40 and 80mg/kg but decreased at 160mg/kg. Superoxide dismutase and nitric oxide increased with increasing doses of aspartame, while aspartate levels showed no significant difference. CONCLUSION The study showed morphological alterations consistent with neuronal injury and biochemical changes of oxidative stress. These data therefore supports the need for caution in the indiscriminate use of aspartame as a non-nutritive sweetener.
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Affiliation(s)
- Adejoke Y Onaolapo
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomosho, Oyo State, Nigeria; Department of Anatomy and Cell Biology, Faculty of Basic Medical Sciences, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.
| | - Olakunle J Onaolapo
- Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, College of Health Sciences, Ladoke Akintola University of Technology, Oshogbo, Osun State, Nigeria.
| | - Polycarp U Nwoha
- Department of Anatomy and Cell Biology, Faculty of Basic Medical Sciences, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
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Connectome and molecular pharmacological differences in the dopaminergic system in restless legs syndrome (RLS): plastic changes and neuroadaptations that may contribute to augmentation. Sleep Med 2016; 31:71-77. [PMID: 27539027 DOI: 10.1016/j.sleep.2016.06.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/21/2016] [Accepted: 06/04/2016] [Indexed: 01/08/2023]
Abstract
Restless legs syndrome (RLS) is primarily treated with levodopa and dopaminergics that target the inhibitory dopamine receptor subtypes D3 and D2. The initial success of this therapy led to the idea of a hypodopaminergic state as the mechanism underlying RLS. However, multiple lines of evidence suggest that this simplified concept of a reduced dopamine function as the basis of RLS is incomplete. Moreover, long-term medication with the D2/D3 agonists leads to a reversal of the initial benefits of dopamine agonists and augmentation, which is a worsening of symptoms under therapy. The recent findings on the state of the dopamine system in RLS that support the notion that a dysfunction in the dopamine system may in fact induce a hyperdopaminergic state are summarized. On the basis of these data, the concept of a dynamic nature of the dopamine effects in a circadian context is presented. The possible interactions of cell adhesion molecules expressed by the dopaminergic systems and their possible effects on RLS and augmentation are discussed. Genome-wide association studies (GWAS) indicate a significantly increased risk for RLS in populations with genomic variants of the cell adhesion molecule receptor type protein tyrosine phosphatase D (PTPRD), and PTPRD is abundantly expressed by dopamine neurons. PTPRD may play a role in the reconfiguration of neural circuits, including shaping the interplay of G protein-coupled receptor (GPCR) homomers and heteromers that mediate dopaminergic modulation. Recent animal model data support the concept that interactions between functionally distinct dopamine receptor subtypes can reshape behavioral outcomes and change with normal aging. Additionally, long-term activation of one dopamine receptor subtype can increase the receptor expression of a different receptor subtype with opposite modulatory actions. Such dopamine receptor interactions at both spinal and supraspinal levels appear to play important roles in RLS. In addition, these interactions can extend to the adenosine A1 and A2A receptors, which are also prominently expressed in the striatum. Interactions between adenosine and dopamine receptors and dopaminergic cell adhesion molecules, including PTPRD, may provide new pharmacological targets for treating RLS. In summary, new treatment options for RLS that include recovery from augmentation will have to consider dynamic changes in the dopamine system that occur during the circadian cycle, plastic changes that can develop as a function of treatment or with aging, changes in the connectome based on alterations in cell adhesion molecules, and receptor interactions that may extend beyond the dopamine system itself.
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Deep-brain photoreception links luminance detection to motor output in Xenopus frog tadpoles. Proc Natl Acad Sci U S A 2016; 113:6053-8. [PMID: 27166423 DOI: 10.1073/pnas.1515516113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Nonvisual photoreceptors are widely distributed in the retina and brain, but their roles in animal behavior remain poorly understood. Here we document a previously unidentified form of deep-brain photoreception in Xenopus laevis frog tadpoles. The isolated nervous system retains sensitivity to light even when devoid of input from classical eye and pineal photoreceptors. These preparations produce regular bouts of rhythmic swimming activity in ambient light but fall silent in the dark. This sensitivity is tuned to short-wavelength UV light; illumination at 400 nm initiates motor activity over a broad range of intensities, whereas longer wavelengths do not cause a response. The photosensitive tissue is located in a small region of caudal diencephalon-this region is necessary to retain responses to illumination, whereas its focal illumination is sufficient to drive them. We present evidence for photoreception via the light-sensitive proteins opsin (OPN)5 and/or cryptochrome 1, because populations of OPN5-positive and cryptochrome-positive cells reside within the caudal diencephalon. This discovery represents a hitherto undescribed vertebrate pathway that links luminance detection to motor output. The pathway provides a simple mechanism for light avoidance and/or may reinforce classical circadian systems.
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Currie SP, Combes D, Scott NW, Simmers J, Sillar KT. A behaviorally related developmental switch in nitrergic modulation of locomotor rhythmogenesis in larval Xenopus tadpoles. J Neurophysiol 2016; 115:1446-57. [PMID: 26763775 PMCID: PMC4808108 DOI: 10.1152/jn.00283.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 01/11/2016] [Indexed: 12/23/2022] Open
Abstract
Locomotor control requires functional flexibility to support an animal's full behavioral repertoire. This flexibility is partly endowed by neuromodulators, allowing neural networks to generate a range of motor output configurations. In hatchling Xenopus tadpoles, before the onset of free-swimming behavior, the gaseous modulator nitric oxide (NO) inhibits locomotor output, shortening swim episodes and decreasing swim cycle frequency. While populations of nitrergic neurons are already present in the tadpole's brain stem at hatching, neurons positive for the NO-synthetic enzyme, NO synthase, subsequently appear in the spinal cord, suggesting additional as yet unidentified roles for NO during larval development. Here, we first describe the expression of locomotor behavior during the animal's change from an early sessile to a later free-swimming lifestyle and then compare the effects of NO throughout tadpole development. We identify a discrete switch in nitrergic modulation from net inhibition to overall excitation, coincident with the transition to free-swimming locomotion. Additionally, we show in isolated brain stem-spinal cord preparations of older larvae that NO's excitatory effects are manifested as an increase in the probability of spontaneous swim episode occurrence, as found previously for the neurotransmitter dopamine, but that these effects are mediated within the brain stem. Moreover, while the effects of NO and dopamine are similar, the two modulators act in parallel rather than NO operating serially by modulating dopaminergic signaling. Finally, NO's activation of neurons in the brain stem also leads to the release of NO in the spinal cord that subsequently contributes to NO's facilitation of swimming.
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Affiliation(s)
- Stephen P Currie
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife, Scotland, United Kingdom; and
| | - Denis Combes
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, Bordeaux, France
| | - Nicholas W Scott
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife, Scotland, United Kingdom; and
| | - John Simmers
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, Bordeaux, France
| | - Keith T Sillar
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife, Scotland, United Kingdom; and
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Kishore S, McLean DL. Neuromodulation: letting sources of spinal dopamine speak for themselves. Curr Biol 2015; 25:R146-8. [PMID: 25689908 DOI: 10.1016/j.cub.2015.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A recent study of dopaminergic neurons in the brain of larval zebrafish has important implications for interpreting the natural actions of neuromodulators in the spinal cord.
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Affiliation(s)
- Sandeep Kishore
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - David L McLean
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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GABAAergic inhibition or dopamine denervation of the A11 hypothalamic nucleus induces trigeminal analgesia. Pain 2015; 156:644-655. [PMID: 25790455 DOI: 10.1097/j.pain.0000000000000091] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Descending pain-modulatory systems, either inhibitory or facilitatory, play a critical role in both acute and chronic pain. Compared with serotonin and norepinephrine, little is known about the function of dopamine (DA). We characterized the anatomical organization of descending DA pathways from hypothalamic A11 nuclei to the medullary dorsal horn (MDH) and investigated their role in trigeminal pain. Immunochemistry analysis reveals that A11 is a heterogeneous nucleus that contains at least 3 neuronal phenotypes, DA, GABA, and alpha-calcitonin gene-related peptide (α-CGRP) neurons, exhibiting different distribution patterns, with a large proportion of GABA relative to DA neurons. Using fluorogold, we show that descending pathways from A11 nuclei to MDH originate mainly from DA neurons and are bilateral. Facial nociceptive stimulation elevates Fos immunoreactivity in both ipsilateral and contralateral A11 nuclei. Fos immunoreactivity is not detected in DA or projecting neurons but, interestingly, in GABA neurons. Finally, inactivating A11, using muscimol, or partially lesioning A11 DA neurons, using the neurotoxin 6-hydroxydopamine, inhibits trigeminal pain behavior. These results show that A11 nuclei are involved in pain processing. Interestingly, however, pain seems to activate GABAergic neurons within A11 nuclei, which suggests that pain inhibits rather than activates descending DA controls. We show that such inhibition produces an antinociceptive effect. Pain-induced inhibition of descending DA controls and the resulting reduced DA concentration within the dorsal horn may inhibit the transfer of nociceptive information to higher brain centers through preferential activation of dorsal horn D2-like receptors.
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Keeler BE, Lallemand P, Patel MM, de Castro Brás LE, Clemens S. Opposing aging-related shift of excitatory dopamine D1 and inhibitory D3 receptor protein expression in striatum and spinal cord. J Neurophysiol 2015; 115:363-9. [PMID: 26561599 DOI: 10.1152/jn.00390.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 11/06/2015] [Indexed: 12/18/2022] Open
Abstract
Normal aging is associated with a decrease in motor function, a concomitant increase in muscle stiffness and tone, and a decrease in dopamine (DA) levels in the spinal cord. The striatum plays a critical role in the control of motor function, and it receives strong DA innervation from the substantia nigra. However, locomotor activity also requires the activation of motoneurons in the lumbar spinal cord, which in the mouse express all five DA receptor subtypes (D1-D5). Of these, the D3 receptor (D3R) expresses the highest affinity to DA and mediates inhibitory actions, while activation of the lower-affinity D1 receptor (D1R) system promotes excitatory effects. To test whether the aging-related decrease in DA levels is associated with corresponding changes in DA receptor protein expression levels, we probed with Western blot and immunohistochemical techniques for D1R and D3R protein expression levels over the normal life span of the mouse. We found that with age D1R expression levels increased in both striatum and spinal cord, while D3R expression levels remained stable in the striatum or slightly decreased in the spinal cord. The resulting D1-to-D3 ratio indicates a strong upregulation of D1R-mediated pathways in old animals, which is particularly pronounced in the lumbar spinal cord. These data suggest that aging may be associated with a shift in DA-mediated pathways in striatum and spinal cord, which in turn could be an underlying factor in the emergence of aging- and DA-related motor dysfunctions such as Parkinson's disease or Restless Legs Syndrome (RLS).
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Affiliation(s)
- Benjamin E Keeler
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Perrine Lallemand
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Mukund M Patel
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Lisandra E de Castro Brás
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
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Acevedo J, Santana-Almansa A, Matos-Vergara N, Marrero-Cordero LR, Cabezas-Bou E, Díaz-Ríos M. Caffeine stimulates locomotor activity in the mammalian spinal cord via adenosine A1 receptor-dopamine D1 receptor interaction and PKA-dependent mechanisms. Neuropharmacology 2015; 101:490-505. [PMID: 26493631 DOI: 10.1016/j.neuropharm.2015.10.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/16/2015] [Accepted: 10/15/2015] [Indexed: 01/31/2023]
Abstract
Caffeine is a potent psychostimulant that can have significant and widely variable effects on the activity of multiple neuronal pathways. The most pronounced caffeine-induced behavioral effect seen in rodents is to increase locomotor activity which has been linked to a dose-dependent inhibition of A1 and A(2A) receptors. The effects of caffeine at the level of the lumbar spinal central pattern generator (CPG) network for hindlimb locomotion are lacking. We assessed the effects of caffeine to the locomotor function of the spinal CPG network via extracellular ventral root recordings using the isolated neonatal mouse spinal cord preparation. Addition of caffeine and of an A1 receptor antagonist significantly decreased the cycle period accelerating the ongoing locomotor rhythm, while decreasing burst duration reversibly in most preparations suggesting the role of A1 receptors as the primary target of caffeine. Caffeine and an A1 receptor antagonist failed to stimulate ongoing locomotor activity in the absence of dopamine or in the presence of a D1 receptor antagonist supporting A1/D1 receptor-dependent mechanism of action. The use of caffeine or an A1 receptor blocker failed to stimulate an ongoing locomotor rhythm in the presence of a blocker of the cAMP-dependent protein kinase (PKA) supporting the need of this intracellular pathway for the modulatory effects of caffeine to occur. These results support a stimulant effect of caffeine on the lumbar spinal network controlling hindlimb locomotion through the inhibition of A1 receptors and subsequent activation of D1 receptors via a PKA-dependent intracellular mechanism.
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Affiliation(s)
- JeanMarie Acevedo
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR 00936, USA
| | - Alexandra Santana-Almansa
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR 00936, USA
| | - Nikol Matos-Vergara
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR 00936, USA
| | - Luis René Marrero-Cordero
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR 00936, USA
| | - Ernesto Cabezas-Bou
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR 00936, USA
| | - Manuel Díaz-Ríos
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR 00936, USA.
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Full anatomical recovery of the dopaminergic system after a complete spinal cord injury in lampreys. Neural Plast 2015; 2015:350750. [PMID: 25861481 PMCID: PMC4378702 DOI: 10.1155/2015/350750] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Revised: 02/18/2015] [Accepted: 03/02/2015] [Indexed: 12/11/2022] Open
Abstract
Following a spinal injury, lampreys at first are paralyzed below the level of transection. However, they recover locomotion after several weeks, and this is accompanied by the regeneration of descending axons from the brain and the production of new neurons in the spinal cord. Here, we aimed to analyse the changes in the dopaminergic system of the sea lamprey after a complete spinal transection by studying the changes in dopaminergic cell numbers and dopaminergic innervation in the spinal cord. Changes in the expression of the D2 receptor were also studied. We report the full anatomical regeneration of the dopaminergic system after an initial decrease in the number of dopaminergic cells and fibres. Numbers of dopaminergic cells were recovered rostrally and caudally to the site of injury. Quantification of dopaminergic profiles revealed the full recovery of the dopaminergic innervation of the spinal cord rostral and caudal to the site of injury. Interestingly, no changes in the expression of the D2 receptor were observed at time points in which a reduced dopaminergic innervation of the spinal cord was observed. Our observations reveal that in lampreys a spinal cord injury is followed by the full anatomical recovery of the dopaminergic system.
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