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Ringuet MT, Koo A, Furness SGB, McDougall SJ, Furness JB. Sites and mechanisms of action of colokinetics at dopamine, ghrelin and serotonin receptors in the rodent lumbosacral defecation centre. J Physiol 2023; 601:5195-5211. [PMID: 37772438 PMCID: PMC10952827 DOI: 10.1113/jp285217] [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: 07/04/2023] [Accepted: 09/13/2023] [Indexed: 09/30/2023] Open
Abstract
Agonists of dopamine D2 receptors (D2R), 5-hydroxytryptamine (5-HT, serotonin) receptors (5-HTR) and ghrelin receptors (GHSR) activate neurons in the lumbosacral defecation centre, and act as 'colokinetics', leading to increased propulsive colonic motility, in vivo. In the present study, we investigated which neurons in the lumbosacral defecation centre express the receptors and whether dopamine, serotonin and ghrelin receptor agonists act on the same lumbosacral preganglionic neurons (PGNs). We used whole cell electrophysiology to record responses from neurons in the lumbosacral defecation centre, following colokinetic application, and investigated their expression profiles and the chemistries of their neural inputs. Fluorescence in situ hybridisation revealed Drd2, Ghsr and Htr2C transcripts were colocalised in lumbosacral PGNs of mice, and immunohistochemistry showed that these neurons have closely associated tyrosine hydroxylase and 5-HT boutons. Previous studies showed that they do not receive ghrelin inputs. Whole cell electrophysiology in adult mice spinal cord revealed that dopamine, serotonin, α-methylserotonin and capromorelin each caused inward, excitatory currents in overlapping populations of lumbosacral PGNs. Furthermore, dopamine caused increased frequency of both IPSCs and EPSCs in a cohort of D2R neurons. Tetrodotoxin blocked the IPSCs and EPSCs, revealing a post-synaptic excitatory action of dopamine. In lumbosacral PGNs of postnatal day 7-14 rats, only dopamine's postsynaptic effects were observed. Furthermore, inward, excitatory currents evoked by dopamine were reduced by the GHSR antagonist, YIL781. We conclude that lumbosacral PGNs are the site where the action of endogenous ligands of D2R and 5-HT2R converge, and that GHSR act as a cis-modulator of D2R expressed by the same neurons. KEY POINTS: Dopamine, 5-hydroxytryptamine (5-HT, serotonin) and ghrelin (GHSR) receptor agonists increase colorectal motility and have been postulated to act at receptors on parasympathetic preganglionic neurons (PGNs) in the lumbosacral spinal cord. We aimed to determine which neurons in the lumbosacral spinal cord express dopamine, serotonin and GHSR receptors, their neural inputs, and whether agonists at these receptors excite them. We show that dopamine, serotonin and ghrelin receptor transcripts are contained in the same PGNs and that these neurons have closely associated tyrosine hydroxylase and serotonin boutons. Whole cell electrophysiology revealed that dopamine, serotonin and GHSR receptor agonists induce an inward excitatory current in overlapping populations of lumbosacral PGNs. Dopamine-induced excitation was reversed by GHSR antagonism. The present study demonstrates that lumbosacral PGNs are the site at which actions of endogenous ligands of dopamine D2 receptors and 5-HT type 2 receptors converge. Ghrelin receptors are functional, but their role appears to be as modulators of dopamine effects at D2 receptors.
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Affiliation(s)
- Mitchell T. Ringuet
- Department of Anatomy & PhysiologyUniversity of MelbourneMelbourneVICAustralia
| | - Ada Koo
- Department of Anatomy & PhysiologyUniversity of MelbourneMelbourneVICAustralia
| | - Sebastian G. B. Furness
- School of Biomedical SciencesUniversity of QueenslandBrisbaneQLDAustralia
- Monash Institute of Pharmaceutical SciencesMelbourneVICAustralia
| | - Stuart J. McDougall
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneMelbourneVICAustralia
| | - John B. Furness
- Department of Anatomy & PhysiologyUniversity of MelbourneMelbourneVICAustralia
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneMelbourneVICAustralia
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Recabal-Beyer A, Tavakoli H, M M Senecal J, Stecina K, Nagy JI. Interrelationships between spinal sympathetic preganglionic neurons, autonomic systems and electrical synapses formed by connexin36-containing gap junctions. Neuroscience 2023:S0306-4522(23)00220-8. [PMID: 37225049 DOI: 10.1016/j.neuroscience.2023.05.009] [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: 11/23/2022] [Revised: 04/24/2023] [Accepted: 05/14/2023] [Indexed: 05/26/2023]
Abstract
Spinal sympathetic preganglionic neurons (SPNs) are among the many neuronal populations in the mammalian central nervous system (CNS) where there is evidence for electrical coupling between cell pairs linked by gap junctions composed of connexin36 (Cx36). Understanding the organization of this coupling in relation to autonomic functions of spinal sympathetic systems requires knowledge of how these junctions are deployed among SPNs. Here, we document the distribution of immunofluorescence detection of Cx36 among SPNs identified by immunolabelling of their various markers, including choline acetyltransferase, nitric oxide and peripherin in adult and developing mouse and rat. In adult animals, labelling of Cx36 was exclusively punctate and dense concentrations of Cx36-puncta were distributed along the entire length of the spinal thoracic intermediolateral cell column (IML). These puncta were also seen in association with SPN dendritic processes in the lateral funiculus, the intercalated and central autonomic areas and those within and extending medially from the IML. All labelling for Cx36 was absent in spinal cords of Cx36 knockout mice. High densities of Cx36-puncta were already evident among clusters of SPNs in the IML of mouse and rat at postnatal days 10-12. In Cx36BAC::eGFP mice, eGFP reporter was absent in SPNs, thus representing false negative detection, but was localized to some glutamatergic and GABAergic synaptic terminals. Some eGFP+ terminals were found contacting SPN dendrites. These results indicate widespread Cx36 expression in SPNs, further supporting evidence of electrical coupling between these cells, and suggest that SPNs are innervated by neurons that themselves may be electrically coupled.
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Affiliation(s)
- A Recabal-Beyer
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada R3E 0J9
| | - H Tavakoli
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada R3E 0J9
| | - J M M Senecal
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada R3E 0J9
| | - K Stecina
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada R3E 0J9
| | - J I Nagy
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada R3E 0J9.
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Barioni NO, Derakhshan F, Tenorio Lopes L, Onimaru H, Roy A, McDonald F, Scheibli E, Baghdadwala MI, Heidari N, Bharadia M, Ikeda K, Yazawa I, Okada Y, Harris MB, Dutschmann M, Wilson RJA. Novel oxygen sensing mechanism in the spinal cord involved in cardiorespiratory responses to hypoxia. SCIENCE ADVANCES 2022; 8:eabm1444. [PMID: 35333571 PMCID: PMC8956269 DOI: 10.1126/sciadv.abm1444] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 02/04/2022] [Indexed: 05/05/2023]
Abstract
As blood oxygenation decreases (hypoxemia), mammals mount cardiorespiratory responses, increasing oxygen to vital organs. The carotid bodies are the primary oxygen chemoreceptors for breathing, but sympathetic-mediated cardiovascular responses to hypoxia persist in their absence, suggesting additional high-fidelity oxygen sensors. We show that spinal thoracic sympathetic preganglionic neurons are excited by hypoxia and silenced by hyperoxia, independent of surrounding astrocytes. These spinal oxygen sensors (SOS) enhance sympatho-respiratory activity induced by CNS asphyxia-like stimuli, suggesting they bestow a life-or-death advantage. Our data suggest the SOS use a mechanism involving neuronal nitric oxide synthase 1 (NOS1) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). We propose NOS1 serves as an oxygen-dependent sink for NADPH in hyperoxia. In hypoxia, NADPH catabolism by NOS1 decreases, increasing availability of NADPH to NOX and launching reactive oxygen species-dependent processes, including transient receptor potential channel activation. Equipped with this mechanism, SOS are likely broadly important for physiological regulation in chronic disease, spinal cord injury, and cardiorespiratory crisis.
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Affiliation(s)
- Nicole O. Barioni
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Fatemeh Derakhshan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Luana Tenorio Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan
| | - Arijit Roy
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Fiona McDonald
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Erika Scheibli
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Mufaddal I. Baghdadwala
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Negar Heidari
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Manisha Bharadia
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Keiko Ikeda
- Division of Internal Medicine, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Itaru Yazawa
- Global Research Center for Innovative Life Science, Peptide Drug Innovation, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo 142-8501, Japan
| | - Yasumasa Okada
- Division of Internal Medicine, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Michael B. Harris
- Department of Biological Sciences, California State University Long Beach, Long Beach, CA 90840, USA
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, 3052, Australia
| | - Richard J. A. Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Sachdeva R, Hutton G, Marwaha AS, Krassioukov AV. Morphological maladaptations in sympathetic preganglionic neurons following an experimental high-thoracic spinal cord injury. Exp Neurol 2020; 327:113235. [PMID: 32044331 DOI: 10.1016/j.expneurol.2020.113235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 01/15/2020] [Accepted: 02/06/2020] [Indexed: 10/25/2022]
Abstract
Spinal cord injury (SCI) disrupts the supraspinal vasomotor pathways to sympathetic preganglionic neurons (SPNs) leading to impaired blood pressure (BP) control that often results in episodes of autonomic dysreflexia and orthostatic hypotension. The physiological cardiovascular consequences of SCI are largely attributed to the plastic changes in spinal SPNs induced by their partial deafferentation. While multiple studies have investigated the morphological changes in SPNs following SCI with contrasting reports. Here we investigated the morphological changes in SPNs rostral and caudal to a high thoracic (T3) SCI at 1-, 4- and 8-weeks post injury. SPNs were identified using Nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH- diaphorase) staining and were quantified for soma size and various dendritic measurements. We show that rostral to the lesion, soma size was increased at 1 week along with increased dendritic arbor. The total dendritic length was also increased at chronic stage (8 weeks post SCI). Caudal to the lesion, the soma size or dendritic lengths did not change with SCI. However, dendritic branching was enhanced within a week post SCI and remained elevated throughout the chronic stages. These findings demonstrate that SPNs undergo significant structural changes form sub-acute to chronic stages post-SCI that likely determines their functional consequences. These changes are discussed in context of physiological cardiovascular outcomes post-SCI.
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Affiliation(s)
- Rahul Sachdeva
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Gillian Hutton
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Arshdeep S Marwaha
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada; GF Strong Rehabilitation Center, Vancouver Coastal Health, Vancouver, Canada.
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Su CK, Chen YY, Ho CM. Nitric Oxide Orchestrates a Power-Law Modulation of Sympathetic Firing Behaviors in Neonatal Rat Spinal Cords. Front Physiol 2018; 9:163. [PMID: 29559921 PMCID: PMC5845561 DOI: 10.3389/fphys.2018.00163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
Nitric oxide (NO) is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using in vitro preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM). NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors), indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker), gabazine (a GABAA receptor blocker), or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker) also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor) pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor activities were found to participate in plFM by both components. In contrast, GABAA receptor activities are involved in the component of fractional reduction only. These findings suggest that NO orchestrates a repertoire of excitatory and inhibitory neurotransmissions, incurs a shunting effect on postsynaptic membrane properties, and thus, alters sympathetic firing in a manner of plFM. We propose that the plFM mediated by NO forms a basic scheme of differential controls for heterogeneous sympathetic regulation of visceral functions.
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Affiliation(s)
- Chun-Kuei Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Yin Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chiu-Ming Ho
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
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6
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Zhang D, Lv G. Therapeutic potential of spinal GLP-1 receptor signaling. Peptides 2018; 101:89-94. [PMID: 29329976 DOI: 10.1016/j.peptides.2018.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/24/2017] [Accepted: 01/08/2018] [Indexed: 12/16/2022]
Abstract
GLP-1 signaling pathway has been well studied for its role in regulating glucose homeostasis, as well as its beneficial effects in energy and nutrient metabolism. A number of drugs based on GLP-1 have been used to treat type 2 diabetes mellitus. GLP-1R is expressed in multiple organs and numerous experimental studies have demonstrated that GLP-1 signaling pathway exhibits pro-survival functions in various disorders. In the central nervous system, stimulation of GLP-1R produces neuroprotective effects in specific neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. The preproglucagon neurons located in the brainstem can also produce GLP-1. GLP-1 analogs have a long-acting effect and are able to pass the blood-brain barrier, which probably extends the therapeutic efficacy of GLP-1R activation. Neurodegenerative or traumatic conditions can damage the spinal cord and result in motor and sensory dysfunction. Evidence supports that GLP-1R activation in the spinal cord possesses beneficial effects and significant therapeutic potential. Herein, we review studies that have focused on GLP-1 and the spinal cord, and summarize the expression of GLP-1R and the innervation of PPG neurons in the spinal cord, as well as the potential therapeutic benefits of GLP-1R activation.
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Affiliation(s)
- Dongao Zhang
- Department of Orthopaedics, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Gang Lv
- Department of Orthopaedics, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China.
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Poon YY, Tsai CY, Cheng CD, Chang AYW, Chan SHH. Endogenous nitric oxide derived from NOS I or II in thoracic spinal cord exerts opposing tonic modulation on sympathetic vasomotor tone via disparate mechanisms in anesthetized rats. Am J Physiol Heart Circ Physiol 2016; 311:H555-62. [PMID: 27371683 DOI: 10.1152/ajpheart.00246.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/29/2016] [Indexed: 11/22/2022]
Abstract
The sympathetic preganglionic neurons (SPN) in the thoracic spinal cord regulate vasomotor tone via norepinephrine released from sympathetic terminals and adrenal medulla. We assessed the hypothesis that nitric oxide synthase I (NOS I)- and NOS II-derived nitric oxide (NO) in the thoracic spinal cord differentially modulate sympathetic outflow and that the adrenal medulla may be involved in those modulatory actions. In Sprague-Dawley rats, NOS I immunoreactivity was distributed primarily in the perikaryon, proximal dendrites, or axons of SPN, and small clusters of NOS II immunoreactivity impinged mainly on the circumference of SPN. Intrathecal administration of 7-nitroindazole (7-NI), a specific NOS I antagonist, into the thoracic spinal cord significantly reduced arterial pressure, heart rate, and basal or baroreflex-mediated sympathetic vasomotor tone. On the other hand, intrathecal application of S-methylisothiourea (SMT), a specific NOS II antagonist, elevated arterial pressure with a transient reduction of heart rate, induced a surge of plasma norepinephrine, and reduced baroreflex-mediated but not basal sympathetic vasomotor tone. Bilateral adrenalectomy significantly exacerbated the cardiovascular responses to 7-NI but antagonized those to SMT. We conclude that both NOS I and NOS II are present in the thoracic spinal cord and are tonically active under physiological conditions. Furthermore, the endogenous NO generated by NOS I-containing SPN exerts a tonic excitatory action on vasomotor tone mediated by norepinephrine released from the adrenal medulla and sympathetic nerve terminals. On the other hand, NO derived from NOS II exerts a tonic inhibitory action on sympathetic outflow from the SPN that targets primarily the blood vessels.
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Affiliation(s)
- Yan-Yuen Poon
- Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China; Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Ching-Yi Tsai
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Chung-Dar Cheng
- Department of Nuclear Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China; and
| | - Alice Y W Chang
- Institute of Physiology, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Samuel H H Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China;
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Wehrwein EA, Orer HS, Barman SM. Overview of the Anatomy, Physiology, and Pharmacology of the Autonomic Nervous System. Compr Physiol 2016; 6:1239-78. [PMID: 27347892 DOI: 10.1002/cphy.c150037] [Citation(s) in RCA: 227] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Comprised of the sympathetic nervous system, parasympathetic nervous system, and enteric nervous system, the autonomic nervous system (ANS) provides the neural control of all parts of the body except for skeletal muscles. The ANS has the major responsibility to ensure that the physiological integrity of cells, tissues, and organs throughout the entire body is maintained (homeostasis) in the face of perturbations exerted by both the external and internal environments. Many commonly prescribed drugs, over-the-counter drugs, toxins, and toxicants function by altering transmission within the ANS. Autonomic dysfunction is a signature of many neurological diseases or disorders. Despite the physiological relevance of the ANS, most neuroscience textbooks offer very limited coverage of this portion of the nervous system. This review article provides both historical and current information about the anatomy, physiology, and pharmacology of the sympathetic and parasympathetic divisions of the ANS. The ultimate aim is for this article to be a valuable resource for those interested in learning the basics of these two components of the ANS and to appreciate its importance in both health and disease. Other resources should be consulted for a thorough understanding of the third division of the ANS, the enteric nervous system. © 2016 American Physiological Society. Compr Physiol 6:1239-1278, 2016.
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Affiliation(s)
- Erica A Wehrwein
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Hakan S Orer
- Department of Pharmacology, Koc University School of Medicine, Istanbul, Turkey
| | - Susan M Barman
- Department of Pharmacology &Toxicology, Michigan State University, East Lansing, Michigan, USA
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Deuchars SA, Lall VK. Sympathetic preganglionic neurons: properties and inputs. Compr Physiol 2016; 5:829-69. [PMID: 25880515 DOI: 10.1002/cphy.c140020] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The sympathetic nervous system comprises one half of the autonomic nervous system and participates in maintaining homeostasis and enabling organisms to respond in an appropriate manner to perturbations in their environment, either internal or external. The sympathetic preganglionic neurons (SPNs) lie within the spinal cord and their axons traverse the ventral horn to exit in ventral roots where they form synapses onto postganglionic neurons. Thus, these neurons are the last point at which the central nervous system can exert an effect to enable changes in sympathetic outflow. This review considers the degree of complexity of sympathetic control occurring at the level of the spinal cord. The morphology and targets of SPNs illustrate the diversity within this group, as do their diverse intrinsic properties which reveal some functional significance of these properties. SPNs show high degrees of coupled activity, mediated through gap junctions, that enables rapid and coordinated responses; these gap junctions contribute to the rhythmic activity so critical to sympathetic outflow. The main inputs onto SPNs are considered; these comprise afferent, descending, and interneuronal influences that themselves enable functionally appropriate changes in SPN activity. The complexity of inputs is further demonstrated by the plethora of receptors that mediate the different responses in SPNs; their origins and effects are plentiful and diverse. Together these different inputs and the intrinsic and coupled activity of SPNs result in the rhythmic nature of sympathetic outflow from the spinal cord, which has a variety of frequencies that can be altered in different conditions.
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Affiliation(s)
- Susan A Deuchars
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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Parker LM, Damanhuri HA, Fletcher SP, Goodchild AK. Hydralazine administration activates sympathetic preganglionic neurons whose activity mobilizes glucose and increases cardiovascular function. Brain Res 2015; 1604:25-34. [DOI: 10.1016/j.brainres.2015.01.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 01/27/2015] [Accepted: 01/29/2015] [Indexed: 11/16/2022]
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Llewellyn-Smith IJ, Marina N, Manton RN, Reimann F, Gribble FM, Trapp S. Spinally projecting preproglucagon axons preferentially innervate sympathetic preganglionic neurons. Neuroscience 2014; 284:872-887. [PMID: 25450967 PMCID: PMC4300405 DOI: 10.1016/j.neuroscience.2014.10.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/21/2014] [Accepted: 10/24/2014] [Indexed: 12/29/2022]
Abstract
Spinal GLP-1 axons target primarily sympathetic preganglionic neurons. Spinal GLP-1 axons innervate interneurons that may regulate sympathetic outflow. Many GLP-1 neurons in the medulla are spinally-projecting. The lumbar cord contains YFP-expressing neurons that do not innervate the brain.
Glucagon-like peptide-1 (GLP-1) affects central autonomic neurons, including those controlling the cardiovascular system, thermogenesis, and energy balance. Preproglucagon (PPG) neurons, located mainly in the nucleus tractus solitarius (NTS) and medullary reticular formation, produce GLP-1. In transgenic mice expressing glucagon promoter-driven yellow fluorescent protein (YFP), these brainstem PPG neurons project to many central autonomic regions where GLP-1 receptors are expressed. The spinal cord also contains GLP-1 receptor mRNA but the distribution of spinal PPG axons is unknown. Here, we used two-color immunoperoxidase labeling to examine PPG innervation of spinal segments T1–S4 in YFP-PPG mice. Immunoreactivity for YFP identified spinal PPG axons and perikarya. We classified spinal neurons receiving PPG input by immunoreactivity for choline acetyltransferase (ChAT), nitric oxide synthase (NOS) and/or Fluorogold (FG) retrogradely transported from the peritoneal cavity. FG microinjected at T9 defined cell bodies that supplied spinal PPG innervation. The deep dorsal horn of lower lumbar cord contained YFP-immunoreactive neurons. Non-varicose, YFP-immunoreactive axons were prominent in the lateral funiculus, ventral white commissure and around the ventral median fissure. In T1–L2, varicose, YFP-containing axons closely apposed many ChAT-immunoreactive sympathetic preganglionic neurons (SPN) in the intermediolateral cell column (IML) and dorsal lamina X. In the sacral parasympathetic nucleus, about 10% of ChAT-immunoreactive preganglionic neurons received YFP appositions, as did occasional ChAT-positive motor neurons throughout the rostrocaudal extent of the ventral horn. YFP appositions also occurred on NOS-immunoreactive spinal interneurons and on spinal YFP-immunoreactive neurons. Injecting FG at T9 retrogradely labeled many YFP-PPG cell bodies in the medulla but none of the spinal YFP-immunoreactive neurons. These results show that brainstem PPG neurons innervate spinal autonomic and somatic motor neurons. The distributions of spinal PPG axons and spinal GLP-1 receptors correlate well. SPN receive the densest PPG innervation. Brainstem PPG neurons could directly modulate sympathetic outflow through their spinal inputs to SPN or interneurons.
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Affiliation(s)
- I J Llewellyn-Smith
- Cardiovascular Medicine, Physiology and Centre for Neuroscience, Flinders University, Bedford Park, SA 5042, Australia
| | - N Marina
- Department of Metabolism and Experimental Therapeutics, University College London, London WC1E, UK
| | - R N Manton
- Department of Surgery and Cancer & Cell Biology Section, South Kensington Campus, Imperial College, London SW7 2AZ, UK
| | - F Reimann
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - F M Gribble
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - S Trapp
- Department of Surgery and Cancer & Cell Biology Section, South Kensington Campus, Imperial College, London SW7 2AZ, UK; Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E 6BT, UK.
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Parker LM, Kumar NN, Lonergan T, Goodchild AK. Neurochemical codes of sympathetic preganglionic neurons activated by glucoprivation. J Comp Neurol 2013; 521:2703-18. [DOI: 10.1002/cne.23310] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 09/10/2012] [Accepted: 01/15/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Lindsay M. Parker
- The Australian School of Advanced Medicine; Macquarie University; Macquarie Park; 2109 New South Wales; Australia
| | - Natasha N. Kumar
- The Australian School of Advanced Medicine; Macquarie University; Macquarie Park; 2109 New South Wales; Australia
| | - Tina Lonergan
- The Australian School of Advanced Medicine; Macquarie University; Macquarie Park; 2109 New South Wales; Australia
| | - Ann K. Goodchild
- The Australian School of Advanced Medicine; Macquarie University; Macquarie Park; 2109 New South Wales; Australia
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13
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Gnanamanickam GJE, Llewellyn-Smith IJ. Innervation of the rat uterus at estrus: a study in full-thickness, immunoperoxidase-stained whole-mount preparations. J Comp Neurol 2011; 519:621-43. [PMID: 21246547 DOI: 10.1002/cne.22515] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The innervation of the nonpregnant rat uterus has been studied in histological sections, which contain only small samples of nerves and are unlikely to afford a complete picture of uterine innervation. Here we used whole-mount preparations of entire full-thickness uterine horns from nonpregnant rats in estrus to visualize autonomic or sensory nerves with peroxidase immunohistochemistry. Immunoreactivity was studied for tyrosine hydroxylase (TH)-labeled sympathetic nerves; vesicular acetylcholine transporter (VAChT), parasympathetic nerves; and substance P (SP) and calcitonin gene-related peptide (CGRP), sensory nerves. Neuropeptide Y (NPY) and nitric oxide synthase (NOS) identified more than one of these functionally distinct nerve types. Axons of all neurochemical classes entered the uterus at the mesometrium and innervated the uterine smooth muscle. The linea uteri, a dense band of longitudinal muscle opposite the mesometrium, contained more TH-, NPY-, CGRP-, and VAChT-immunoreactive axons than the remaining smooth muscle. Axons immunoreactive for NPY, SP, NOS, and VAChT formed a plexus near the circular muscle-endometrium interface. Rare TH- and NPY-immunoreactive axons and occasional CGRP-immunoreactive axons occurred close to uterine glands. Blood vessels had dense perivascular plexuses of TH- and NPY-containing axons and less dense NOS-, SP-, CGRP-, and VAChT-positive plexuses. The circular muscle plexus and glands were absent opposite the mesometrium. Uterine arterioles formed an interconnected network throughout the uterus. This article provides the first comprehensive description of the autonomic and sensory innervation of the nonpregnant rat uterus and will be a foundation for future studies on changes in uterine innervation caused by normal physiological or pathophysiological challenges.
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Affiliation(s)
- Greta J E Gnanamanickam
- Cardiovascular Medicine, Physiology and Centre for Neuroscience, Flinders University, Bedford Park, South Australia 5042, Australia
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14
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Llewellyn-Smith IJ, Gnanamanickam GJE. Immunoperoxidase detection of neuronal antigens in full-thickness whole mount preparations of hollow organs and thick sections of central nervous tissue. J Neurosci Methods 2010; 196:1-11. [PMID: 21167203 DOI: 10.1016/j.jneumeth.2010.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 12/01/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
Abstract
Immunofluorescently stained whole mounts have proved useful for defining the innervation of the gut and large blood vessels. Nerves supplying other hollow organs are usually studied in sections, which provide much less information. Aiming to describe the entire innervation of rat uterus, we developed a method for immunoperoxidase staining of full-thickness whole mounts that allowed us to visualize all immunoreactive axons. Uterine horns were dissected out, slit open, stretched, pinned flat and fixed. Entire horns were treated with methanol/peroxide, buffered Triton X-100 and normal serum and then incubated in primary antibodies, biotinylated secondary antibodies and avidin-horseradish peroxidase (HRP), each for at least 3 days. Peroxidase reactions revealed immunoreactivity. Immunostained horns were dehydrated, infiltrated with epoxy resin, mounted on slides under Aclar coverslips and polymerized. We treated bladders, gut, major pelvic ganglia and thick sections of perfused medulla oblongata similarly to assess the applicability of the method. Using this method, we could map the entire uterine innervation provided by axons immunoreactive for a variety of antigens. We could also assess the entire tyrosine hydroxylase-immunoreactive innervation in all layers of bladder, gut and ganglia whole mounts and throughout 300 μm sections of medulla. These observations show that this method for immunoperoxidase staining reliably reveals the complete innervation of full-thickness whole mounts of hollow organs and thick sections of central nervous tissue. The method has several advantages. The resin-embedded tissue does not degrade; the immunostaining is non-fading and permanent and neurochemically defined features can be mapped at large scale without confocal microscopy.
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Affiliation(s)
- Ida J Llewellyn-Smith
- Cardiovascular Medicine, Physiology and Centre for Neuroscience, Flinders University, Bedford Park, SA 5042, Australia.
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15
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Ferens DM, Yin L, Ohashi-Doi K, Habgood M, Bron R, Brock JA, Gale JD, Furness JB. Evidence for functional ghrelin receptors on parasympathetic preganglionic neurons of micturition control pathways in the rat. Clin Exp Pharmacol Physiol 2010; 37:926-32. [DOI: 10.1111/j.1440-1681.2010.05409.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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16
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Ferens D, Yin L, Bron R, Hunne B, Ohashi-Doi K, Kitchener P, Sanger G, Witherington J, Shimizu Y, Furness J. Functional and in situ hybridization evidence that preganglionic sympathetic vasoconstrictor neurons express ghrelin receptors. Neuroscience 2010; 166:671-9. [DOI: 10.1016/j.neuroscience.2010.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/01/2010] [Accepted: 01/04/2010] [Indexed: 10/20/2022]
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Chang HY, Havton LA. Anatomical tracer injections into the lower urinary tract may compromise cystometry and external urethral sphincter electromyography in female rats. Neuroscience 2009; 166:212-9. [PMID: 20004710 DOI: 10.1016/j.neuroscience.2009.11.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/13/2009] [Accepted: 11/16/2009] [Indexed: 01/24/2023]
Abstract
Physiological and anatomical investigations are commonly combined in experimental models. When studying the lower urinary tract (LUT), it is often of interest to perform both urodynamic studies and retrogradely labeled neurons innervating the peripheral target organs. However, it is not known whether the use of anatomical tracers for the labeling of, e.g. spinal cord neurons may interfere with the interpretation of the physiological studies on micturition reflexes. We performed cystometry and external urethral sphincter (EUS) electromyography (EMG) under urethane anesthesia in adult female rats at 5-7 days after injection of a 5% fluorogold (FG) solution or vehicle into the major pelvic ganglia (MPG) or the EUS. FG and vehicle injections into the MPG and EUS resulted in decreased voiding efficiency. MPG injections increased the duration of both bladder contractions and the inter-contractile intervals. EUS injections decreased EUS EMG bursting activity during voiding as well as increased both the duration of bladder contractions and the maximum intravesical pressure. In addition, the bladder weight and size were increased after either MPG or EUS injections in both the FG and vehicle groups. We conclude that the injection of anatomical tracers into the MPG and EUS may compromise the interpretation of subsequent urodynamic studies and suggest investigators to consider experimental designs, which allow for physiological assessments to precede the administration of anatomical tracers into the LUT.
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Affiliation(s)
- H-Y Chang
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Llewellyn-Smith IJ. Anatomy of synaptic circuits controlling the activity of sympathetic preganglionic neurons. J Chem Neuroanat 2009; 38:231-9. [DOI: 10.1016/j.jchemneu.2009.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 06/01/2009] [Accepted: 06/02/2009] [Indexed: 01/17/2023]
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