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Leonard EM, Porteus CS, Brink D, Milsom WK. Fish gill chemosensing: knowledge gaps and inconsistencies. J Comp Physiol B 2024:10.1007/s00360-024-01553-5. [PMID: 38758303 DOI: 10.1007/s00360-024-01553-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/04/2024] [Indexed: 05/18/2024]
Abstract
In this review, we explore the inconsistencies in the data and gaps in our knowledge that exist in what is currently known regarding gill chemosensors which drive the cardiorespiratory reflexes in fish. Although putative serotonergic neuroepithelial cells (NEC) dominate the literature, it is clear that other neurotransmitters are involved (adrenaline, noradrenaline, acetylcholine, purines, and dopamine). And although we assume that these agents act on neurons synapsing with the NECs or in the afferent or efferent limbs of the paths between chemosensors and central integration sites, this process remains elusive and may explain current discrepancies or species differences in the literature. To date it has been impossible to link the distribution of NECs to species sensitivity to different stimuli or fish lifestyles and while the gills have been shown to be the primary sensing site for respiratory gases, the location (gills, oro-branchial cavity or elsewhere) and orientation (external/water or internal/blood sensing) of the NECs are highly variable between species of water and air breathing fish. Much of what has been described so far comes from studies of hypoxic responses in fish, however, changes in CO2, ammonia and lactate have all been shown to elicit cardio-respiratory responses and all have been suggested to arise from stimulation of gill NECs. Our view of the role of NECs is broadening as we begin to understand the polymodal nature of these cells. We begin by presenting the fundamental picture of gill chemosensing that has developed, followed by some key unanswered questions about gill chemosensing in general.
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Affiliation(s)
- Erin M Leonard
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Cosima S Porteus
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.
| | - Deidre Brink
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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2
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Okoye CN, Koren SA, Wojtovich AP. Mitochondrial complex I ROS production and redox signaling in hypoxia. Redox Biol 2023; 67:102926. [PMID: 37871533 PMCID: PMC10598411 DOI: 10.1016/j.redox.2023.102926] [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: 08/31/2023] [Revised: 09/29/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023] Open
Abstract
Mitochondria are a main source of cellular energy. Oxidative phosphorylation (OXPHOS) is the major process of aerobic respiration. Enzyme complexes of the electron transport chain (ETC) pump protons to generate a protonmotive force (Δp) that drives OXPHOS. Complex I is an electron entry point into the ETC. Complex I oxidizes nicotinamide adenine dinucleotide (NADH) and transfers electrons to ubiquinone in a reaction coupled with proton pumping. Complex I also produces reactive oxygen species (ROS) under various conditions. The enzymatic activities of complex I can be regulated by metabolic conditions and serves as a regulatory node of the ETC. Complex I ROS plays diverse roles in cell metabolism ranging from physiologic to pathologic conditions. Progress in our understanding indicates that ROS release from complex I serves important signaling functions. Increasing evidence suggests that complex I ROS is important in signaling a mismatch in energy production and demand. In this article, we review the role of ROS from complex I in sensing acute hypoxia.
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Affiliation(s)
- Chidozie N Okoye
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Shon A Koren
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrew P Wojtovich
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA; Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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3
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Millet A, Jendzjowsky N. Pathogen recognition by sensory neurons: hypotheses on the specificity of sensory neuron signaling. Front Immunol 2023; 14:1184000. [PMID: 37207232 PMCID: PMC10189129 DOI: 10.3389/fimmu.2023.1184000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/19/2023] [Indexed: 05/21/2023] Open
Abstract
Sensory neurons cooperate with barrier tissues and resident immune cells to form a significant aspect of defensive strategies in concert with the immune system. This assembly of neuroimmune cellular units is exemplified across evolution from early metazoans to mammalian life. As such, sensory neurons possess the capability to detect pathogenic infiltrates at barrier surfaces. This capacity relies on mechanisms that unleash specific cell signaling, trafficking and defensive reflexes. These pathways exploit mechanisms to amplify and enhance the alerting response should pathogenic infiltration seep into other tissue compartments and/or systemic circulation. Here we explore two hypotheses: 1) that sensory neurons' potential cellular signaling pathways require the interaction of pathogen recognition receptors and ion channels specific to sensory neurons and; 2) mechanisms which amplify these sensing pathways require activation of multiple sensory neuron sites. Where possible, we provide references to other apt reviews which provide the reader more detail on specific aspects of the perspectives provided here.
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Affiliation(s)
- Antoine Millet
- Respiratory & Exercise Physiology, The Lundquist Institute for Biomedical Innovation at Harbor University of California Los Angeles (UCLA) Medical Center, Torrance, CA, United States
| | - Nicholas Jendzjowsky
- Respiratory & Exercise Physiology, The Lundquist Institute for Biomedical Innovation at Harbor University of California Los Angeles (UCLA) Medical Center, Torrance, CA, United States
- Division of Respiratory and Critical Care Medicine and Physiology, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, United States
- *Correspondence: Nicholas Jendzjowsky,
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Holmes AP, Swiderska A, Nathanael D, Aldossary HS, Ray CJ, Coney AM, Kumar P. Are Multiple Mitochondrial Related Signalling Pathways Involved in Carotid Body Oxygen Sensing? Front Physiol 2022; 13:908617. [PMID: 35711317 PMCID: PMC9194093 DOI: 10.3389/fphys.2022.908617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
It is generally acknowledged that the carotid body (CB) type I cell mitochondria are unique, being inhibited by relatively small falls in PaO2 well above those known to inhibit electron transport in other cell types. This feature is suggested to allow for the CB to function as an acute O2 sensor, being stimulated and activating systemic protective reflexes before the metabolism of other cells becomes compromised. What is less clear is precisely how a fall in mitochondrial activity links to type I cell depolarisation, a process that is required for initiation of the chemotransduction cascade and post-synaptic action potential generation. Multiple mitochondrial/metabolic signalling mechanisms have been proposed including local generation of mitochondrial reactive oxygen species (mitoROS), a change in mitochondrial/cellular redox status, a fall in MgATP and an increase in lactate. Although each mechanism is based on compelling experimental evidence, they are all not without question. The current review aims to explore the importance of each of these signalling pathways in mediating the overall CB response to hypoxia. We suggest that there is unlikely to be a single mechanism, but instead multiple mitochondrial related signalling pathways are recruited at different PaO2s during hypoxia. Furthermore, it still remains to be determined if mitochondrial signalling acts independently or in partnership with extra-mitochondrial O2-sensors.
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Affiliation(s)
- Andrew P. Holmes
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Agnieszka Swiderska
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Demitris Nathanael
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Hayyaf S. Aldossary
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- College of Medicine, Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Clare J. Ray
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew M. Coney
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Prem Kumar
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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Iturriaga R, Alcayaga J, Chapleau MW, Somers VK. Carotid body chemoreceptors: physiology, pathology, and implications for health and disease. Physiol Rev 2021; 101:1177-1235. [PMID: 33570461 PMCID: PMC8526340 DOI: 10.1152/physrev.00039.2019] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The carotid body (CB) is the main peripheral chemoreceptor for arterial respiratory gases O2 and CO2 and pH, eliciting reflex ventilatory, cardiovascular, and humoral responses to maintain homeostasis. This review examines the fundamental biology underlying CB chemoreceptor function, its contribution to integrated physiological responses, and its role in maintaining health and potentiating disease. Emphasis is placed on 1) transduction mechanisms in chemoreceptor (type I) cells, highlighting the role played by the hypoxic inhibition of O2-dependent K+ channels and mitochondrial oxidative metabolism, and their modification by intracellular molecules and other ion channels; 2) synaptic mechanisms linking type I cells and petrosal nerve terminals, focusing on the role played by the main proposed transmitters and modulatory gases, and the participation of glial cells in regulation of the chemosensory process; 3) integrated reflex responses to CB activation, emphasizing that the responses differ dramatically depending on the nature of the physiological, pathological, or environmental challenges, and the interactions of the chemoreceptor reflex with other reflexes in optimizing oxygen delivery to the tissues; and 4) the contribution of enhanced CB chemosensory discharge to autonomic and cardiorespiratory pathophysiology in obstructive sleep apnea, congestive heart failure, resistant hypertension, and metabolic diseases and how modulation of enhanced CB reactivity in disease conditions may attenuate pathophysiology.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, and Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Julio Alcayaga
- Laboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Mark W Chapleau
- Department of Internal Medicine, University of Iowa and Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Virend K Somers
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
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Mitochondrial Succinate Metabolism and Reactive Oxygen Species Are Important but Not Essential for Eliciting Carotid Body and Ventilatory Responses to Hypoxia in the Rat. Antioxidants (Basel) 2021; 10:antiox10060840. [PMID: 34070267 PMCID: PMC8225218 DOI: 10.3390/antiox10060840] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 01/31/2023] Open
Abstract
Reflex increases in breathing in response to acute hypoxia are dependent on activation of the carotid body (CB)—A specialised peripheral chemoreceptor. Central to CB O2-sensing is their unique mitochondria but the link between mitochondrial inhibition and cellular stimulation is unresolved. The objective of this study was to evaluate if ex vivo intact CB nerve activity and in vivo whole body ventilatory responses to hypoxia were modified by alterations in succinate metabolism and mitochondrial ROS (mitoROS) generation in the rat. Application of diethyl succinate (DESucc) caused concentration-dependent increases in chemoafferent frequency measuring approximately 10–30% of that induced by severe hypoxia. Inhibition of mitochondrial succinate metabolism by dimethyl malonate (DMM) evoked basal excitation and attenuated the rise in chemoafferent activity in hypoxia. However, approximately 50% of the response to hypoxia was preserved. MitoTEMPO (MitoT) and 10-(6′-plastoquinonyl) decyltriphenylphosphonium (SKQ1) (mitochondrial antioxidants) decreased chemoafferent activity in hypoxia by approximately 20–50%. In awake animals, MitoT and SKQ1 attenuated the rise in respiratory frequency during hypoxia, and SKQ1 also significantly blunted the overall hypoxic ventilatory response (HVR) by approximately 20%. Thus, whilst the data support a role for succinate and mitoROS in CB and whole body O2-sensing in the rat, they are not the sole mediators. Treatment of the CB with mitochondrial selective antioxidants may offer a new approach for treating CB-related cardiovascular–respiratory disorders.
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7
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Prescott SL, Umans BD, Williams EK, Brust RD, Liberles SD. An Airway Protection Program Revealed by Sweeping Genetic Control of Vagal Afferents. Cell 2020; 181:574-589.e14. [PMID: 32259485 PMCID: PMC7197391 DOI: 10.1016/j.cell.2020.03.004] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/08/2020] [Accepted: 03/04/2020] [Indexed: 12/22/2022]
Abstract
Sensory neurons initiate defensive reflexes that ensure airway integrity. Dysfunction of laryngeal neurons is life-threatening, causing pulmonary aspiration, dysphagia, and choking, yet relevant sensory pathways remain poorly understood. Here, we discover rare throat-innervating neurons (∼100 neurons/mouse) that guard the airways against assault. We used genetic tools that broadly cover a vagal/glossopharyngeal sensory neuron atlas to map, ablate, and control specific afferent populations. Optogenetic activation of vagal P2RY1 neurons evokes a coordinated airway defense program-apnea, vocal fold adduction, swallowing, and expiratory reflexes. Ablation of vagal P2RY1 neurons eliminates protective responses to laryngeal water and acid challenge. Anatomical mapping revealed numerous laryngeal terminal types, with P2RY1 neurons forming corpuscular endings that appose laryngeal taste buds. Epithelial cells are primary airway sentinels that communicate with second-order P2RY1 neurons through ATP. These findings provide mechanistic insights into airway defense and a general molecular/genetic roadmap for internal organ sensation by the vagus nerve.
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Affiliation(s)
- Sara L Prescott
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Benjamin D Umans
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Erika K Williams
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Rachael D Brust
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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8
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Abstract
Air-breathing animals do not experience hyperoxia (inspired O2 > 21%) in nature, but preterm and full-term infants often experience hyperoxia/hyperoxemia in clinical settings. This article focuses on the effects of normobaric hyperoxia during the perinatal period on breathing in humans and other mammals, with an emphasis on the neural control of breathing during hyperoxia, after return to normoxia, and in response to subsequent hypoxic and hypercapnic challenges. Acute hyperoxia typically evokes an immediate ventilatory depression that is often, but not always, followed by hyperpnea. The hypoxic ventilatory response (HVR) is enhanced by brief periods of hyperoxia in adult mammals, but the limited data available suggest that this may not be the case for newborns. Chronic exposure to mild-to-moderate levels of hyperoxia (e.g., 30-60% O2 for several days to a few weeks) elicits several changes in breathing in nonhuman animals, some of which are unique to perinatal exposures (i.e., developmental plasticity). Examples of this developmental plasticity include hypoventilation after return to normoxia and long-lasting attenuation of the HVR. Although both peripheral and CNS mechanisms are implicated in hyperoxia-induced plasticity, it is particularly clear that perinatal hyperoxia affects carotid body development. Some of these effects may be transient (e.g., decreased O2 sensitivity of carotid body glomus cells) while others may be permanent (e.g., carotid body hypoplasia, loss of chemoafferent neurons). Whether the hyperoxic exposures routinely experienced by human infants in clinical settings are sufficient to alter respiratory control development remains an open question and requires further research. © 2020 American Physiological Society. Compr Physiol 10:597-636, 2020.
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Affiliation(s)
- Ryan W Bavis
- Department of Biology, Bates College, Lewiston, Maine, USA
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9
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Olson KR, Gao Y, DeLeon ER, Markel TA, Drucker N, Boone D, Whiteman M, Steiger AK, Pluth MD, Tessier CR, Stahelin RV. Extended hypoxia-mediated H 2 S production provides for long-term oxygen sensing. Acta Physiol (Oxf) 2020; 228:e13368. [PMID: 31442361 DOI: 10.1111/apha.13368] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 08/16/2019] [Accepted: 08/18/2019] [Indexed: 12/23/2022]
Abstract
AIM Numerous studies have shown that H2 S serves as an acute oxygen sensor in a variety of cells. We hypothesize that H2 S also serves in extended oxygen sensing. METHODS Here, we compare the effects of extended exposure (24-48 hours) to varying O2 tensions on H2 S and polysulphide metabolism in human embryonic kidney (HEK 293), human adenocarcinomic alveolar basal epithelial (A549), human colon cancer (HTC116), bovine pulmonary artery smooth muscle, human umbilical-derived mesenchymal stromal (stem) cells and porcine tracheal epithelium (PTE) using sulphur-specific fluorophores and fluorometry or confocal microscopy. RESULTS All cells continuously produced H2 S in 21% O2 and H2 S production was increased at lower O2 tensions. Decreasing O2 from 21% to 10%, 5% and 1% O2 progressively increased H2 S production in HEK293 cells and this was partially inhibited by a combination of inhibitors of H2 S biosynthesis, aminooxyacetate, propargyl glycine and compound 3. Mitochondria appeared to be the source of much of this increase in HEK 293 cells. H2 S production in all other cells and PTE increased when O2 was lowered from 21% to 5% except for HTC116 cells where 1% O2 was necessary to increase H2 S, presumably reflecting the hypoxic environment in vivo. Polysulphides (H2 Sn , where n = 2-7), the key signalling metabolite of H2 S also appeared to increase in many cells although this was often masked by high endogenous polysulphide concentrations. CONCLUSION These results show that cellular H2 S is increased during extended hypoxia and they suggest this is a continuously active O2 -sensing mechanism in a variety of cells.
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Affiliation(s)
- Kenneth R. Olson
- Indiana University School of Medicine‐South Bend South Bend Indiana
| | - Yan Gao
- Indiana University School of Medicine‐South Bend South Bend Indiana
| | - Eric R. DeLeon
- Indiana University School of Medicine‐South Bend South Bend Indiana
- Department of Biological Sciences University of Notre Dame Notre Dame Indiana
| | - Troy A. Markel
- Indiana University School of Medicine Riley Hospital for Children at IU Health Indianapolis Indiana
| | - Natalie Drucker
- Indiana University School of Medicine Riley Hospital for Children at IU Health Indianapolis Indiana
| | - David Boone
- Indiana University School of Medicine‐South Bend South Bend Indiana
| | | | - Andrea K. Steiger
- Department of Chemistry and Biochemistry University of Oregon Eugene Oregon
| | - Michael D. Pluth
- Department of Chemistry and Biochemistry University of Oregon Eugene Oregon
| | | | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology Purdue University West Lafayette Indiana
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Hirota K. Basic Biology of Hypoxic Responses Mediated by the Transcription Factor HIFs and its Implication for Medicine. Biomedicines 2020; 8:biomedicines8020032. [PMID: 32069878 PMCID: PMC7168341 DOI: 10.3390/biomedicines8020032] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/08/2020] [Accepted: 02/12/2020] [Indexed: 12/19/2022] Open
Abstract
Oxygen (O2) is essential for human life. Molecular oxygen is vital for the production of adenosine triphosphate (ATP) in human cells. O2 deficiency leads to a reduction in the energy levels that are required to maintain biological functions. O2 acts as the final acceptor of electrons during oxidative phosphorylation, a series of ATP synthesis reactions that occur in conjunction with the electron transport system in mitochondria. Persistent O2 deficiency may cause death due to malfunctioning biological processes. The above account summarizes the classic view of oxygen. However, this classic view has been reviewed over the last two decades. Although O2 is essential for life, higher organisms such as mammals are unable to biosynthesize molecular O2 in the body. Because the multiple organs of higher organisms are constantly exposed to the risk of “O2 deficiency,” living organisms have evolved elaborate strategies to respond to hypoxia. In this review, I will describe the system that governs oxygen homeostasis in the living body from the point-of-view of the transcription factor hypoxia-inducible factor (HIF).
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Affiliation(s)
- Kiichi Hirota
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
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11
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Bernardini A, Wolf A, Brockmeier U, Riffkin H, Metzen E, Acker-Palmer A, Fandrey J, Acker H. Carotid body type I cells engage flavoprotein and Pin1 for oxygen sensing. Am J Physiol Cell Physiol 2020; 318:C719-C731. [PMID: 31967857 DOI: 10.1152/ajpcell.00320.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carotid body (CB) type I cells sense the blood Po2 and generate a nervous signal for stimulating ventilation and circulation when blood oxygen levels decline. Three oxygen-sensing enzyme complexes may be used for this purpose: 1) mitochondrial electron transport chain metabolism, 2) heme oxygenase 2 (HO-2)-generating CO, and/or 3) an NAD(P)H oxidase (NOX). We hypothesize that intracellular redox changes are the link between the sensor and nervous signals. To test this hypothesis type I cell autofluorescence of flavoproteins (Fp) and NAD(P)H within the mouse CB ex vivo was recorded as Fp/(Fp+NAD(P)H) redox ratio. CB type I cell redox ratio transiently declined with the onset of hypoxia. Upon reoxygenation, CB type I cells showed a significantly increased redox ratio. As a control organ, the non-oxygen-sensing sympathetic superior cervical ganglion (SCG) showed a continuously reduced redox ratio upon hypoxia. CN-, diphenyleneiodonium, or reactive oxygen species influenced chemoreceptor discharge (CND) with subsequent loss of O2 sensitivity and inhibited hypoxic Fp reduction only in the CB but not in SCG Fp, indicating a specific role of Fp in the oxygen-sensing process. Hypoxia-induced changes in CB type I cell redox ratio affected peptidyl prolyl isomerase Pin1, which is believed to colocalize with the NADPH oxidase subunit p47phox in the cell membrane to trigger the opening of potassium channels. We postulate that hypoxia-induced changes in the Fp-mediated redox ratio of the CB regulate the Pin1/p47phox tandem to alter type I cell potassium channels and therewith CND.
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Affiliation(s)
- André Bernardini
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Alexandra Wolf
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Ulf Brockmeier
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Helena Riffkin
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Eric Metzen
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Amparo Acker-Palmer
- Institute for Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Joachim Fandrey
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Helmut Acker
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
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12
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Thomsen MT, Lefevre S, Nilsson GE, Wang T, Bayley M. Effects of lactate ions on the cardiorespiratory system in rainbow trout ( Oncorhynchus mykiss). Am J Physiol Regul Integr Comp Physiol 2019; 316:R607-R620. [PMID: 30811217 DOI: 10.1152/ajpregu.00395.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lactate ions are involved in several physiological processes, including a direct stimulation of the carotid body, causing increased ventilation in mammals. A similar mechanism eliciting ventilatory stimulation in other vertebrate classes has been demonstrated, but it remains to be thoroughly investigated. Here, we investigated the effects of lactate ions on the cardiorespiratory system in swimming rainbow trout by manipulating the blood lactate concentration. Lactate elicited a vigorous, dose-dependent elevation of ventilation and bradycardia at physiologically relevant concentrations at constant pH. After this initial confirmation, we examined the chiral specificity of the response and found that only l-lactate induced these effects. By removal of the afferent inputs from the first gill arch, the response was greatly attenuated, and a comparison of the responses to injections up- and downstream of the gills collectively demonstrated that the lactate response was initiated by branchial cells. Injection of specific receptor antagonists revealed that a blockade of serotonergic receptors, which are involved in the hypoxic ventilatory response, significantly reduced the lactate response. Finally, we identified two putative lactate receptors based on sequence homology and found that both were expressed at substantially higher levels in the gills. We propose that lactate ions modulate ventilation by stimulating branchial oxygen-sensing cells, thus eliciting a cardiorespiratory response through receptors likely to have originated early in vertebrate evolution.
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Affiliation(s)
- Mikkel T Thomsen
- Department of Bioscience, Zoophysiology, Aarhus University , Aarhus , Denmark
| | - Sjannie Lefevre
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo , Oslo , Norway
| | - Göran E Nilsson
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo , Oslo , Norway
| | - Tobias Wang
- Department of Bioscience, Zoophysiology, Aarhus University , Aarhus , Denmark.,Aarhus Institute of Advanced Studies, Aarhus University , Aarhus , Denmark
| | - Mark Bayley
- Department of Bioscience, Zoophysiology, Aarhus University , Aarhus , Denmark
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13
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Çakır T, Kayacı S, Aydın MD, Özöner B, Çalık İ, Altınkaynak K. A New Neuropathologic Mechanism of Blood pH Irregularities After Neck Trauma: Importance of Carotid Body-Glossopharyngeal Nerve Network Degeneration. World Neurosurg 2019; 125:e972-e977. [PMID: 30763747 DOI: 10.1016/j.wneu.2019.01.218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 01/04/2023]
Abstract
OBJECTIVE We created a neck trauma model by injecting blood into the sheath of rabbits' carotid bodies (CBs). Then we determined the relationship between neuronal degeneration of the CB due to hemorrhage of this organ and its clinical effects such as blood pH and heart rhythm. METHODS The present study included 24 adult male New Zealand rabbits. The animals were divided into 3 groups: control (n = 5); sham (0.5 mL saline injected into CBs; n = 5); and study (CB trauma model; n = 14). pH values and heart rhythms were recorded before the experiment to determine the values under normal conditions, and measurements were repeated thrice in the days following the experiment. The number of normal and degenerated neuron density of CBs was counted. The relationship between the blood pH values, heart rhythms, and degenerated neuron densities was analyzed. RESULTS Heart rhythms were 218 ± 20 in the control group, 197 ± 16 in the sham group (P = 0.09), and 167 ± 13 in the study group (P < 0.0005). pH values were 7.40 ± 0.041 in the control group, 7.321 ± 0.062 in the sham group (P = 0.203), and 7.23 ± 0.02 in study group (P < 0.0005). Degenerated neuron densities were 12 ± 4/mm3 in the control group, 430 ± 74/mm3 in the sham group (P < 0.005), and 7434 ± 810/mm3 in the study group (P < 0.0001). CONCLUSIONS A high degenerate neuron density in the CB can decrease blood pH and hearth rhythm after neck trauma, and there might be a close relationship between the number of degenerated neurons and clinical findings (such as heart rhythm and blood pH). This relationship suggests that injury to the glossopharyngeal nerve-CB network can cause acidosis by disturbing the breathing-circulating reflex and results in respiratory acidosis.
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Affiliation(s)
- Tayfun Çakır
- Department of Neurosurgery, Medical Faculty of Erzincan Binali Yildirim University, Erzincan, Turkey
| | - Selim Kayacı
- Department of Neurosurgery, Medical Faculty of Erzincan Binali Yildirim University, Erzincan, Turkey
| | - Mehmet Dumlu Aydın
- Department of Neurosurgery, Medical Faculty of Ataturk University, Turkey.
| | - Barış Özöner
- Department of Neurosurgery, Medical Faculty of Erzincan Binali Yildirim University, Erzincan, Turkey
| | - İlknur Çalık
- Department of Pathology, Medical Faculty of Fırat University, Elazığ, Turkey
| | - Konca Altınkaynak
- Department of Biochemistry, Erzurum Research-Training Hospital, Erzurum, Turkey
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14
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Peng YJ, Makarenko VV, Gridina A, Chupikova I, Zhang X, Kumar GK, Fox AP, Prabhakar NR. H 2S mediates carotid body response to hypoxia but not anoxia. Respir Physiol Neurobiol 2019; 259:75-85. [PMID: 30086385 PMCID: PMC6252114 DOI: 10.1016/j.resp.2018.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/16/2018] [Accepted: 08/03/2018] [Indexed: 02/05/2023]
Abstract
The role of cystathionine-γ-lyase (CSE) derived H2S in the hypoxic and anoxic responses of the carotid body (CB) were examined. Experiments were performed on Sprague-Dawley rats, wild type and CSE knockout mice on C57BL/6 J background. Hypoxia (pO2 = 37 ± 3 mmHg) increased the CB sensory nerve activity and elevated H2S levels in rats. In contrast, anoxia (pO2 = 5 ± 4 mmHg) produced only a modest CB sensory excitation with no change in H2S levels. DL-propargylglycine (DL-PAG), a blocker of CSE, inhibited hypoxia but not anoxia-evoked CB sensory excitation and [Ca2+]i elevation of glomus cells. The inhibitory effects of DL-PAG on hypoxia were seen: a) when it is dissolved in saline but not in dimethyl sulfoxide (DMSO), and b) in glomus cells cultured for18 h but not in cells either soon after isolation or after prolonged culturing (72 h) requiring 1-3 h of incubation. On the other hand, anoxia-induced [Ca2+]i responses of glomus cell were blocked by high concentration of DL-PAG (300μM) either alone or in combination with aminooxyacetic acid (AOAA; 300μM) with a decreased cell viability. Anoxia produced a weak CB sensory excitation and robust [Ca2+]i elevation in glomus cells of both wild-type and CSE null mice. As compared to wild-type, CSE null mice exhibited impaired CB chemo reflex as evidenced by attenuated efferent phrenic nerve responses to brief hyperoxia (Dejours test), and hypoxia. Inhalation of 100% N2 (anoxia) depressed breathing in both CSE null and wild-type mice. These observations demonstrate that a) hypoxia and anoxia are not analogous stimuli for studying CB physiology and b) CSE-derived H2S contributes to CB response to hypoxia but not to that of anoxia.
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Affiliation(s)
- Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA.
| | - Vladislav V Makarenko
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Anna Gridina
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Irina Chupikova
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Xiuli Zhang
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Ganesh K Kumar
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Aaron P Fox
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
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15
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Leonard EM, Salman S, Nurse CA. Sensory Processing and Integration at the Carotid Body Tripartite Synapse: Neurotransmitter Functions and Effects of Chronic Hypoxia. Front Physiol 2018; 9:225. [PMID: 29615922 PMCID: PMC5864924 DOI: 10.3389/fphys.2018.00225] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/28/2018] [Indexed: 12/21/2022] Open
Abstract
Maintenance of homeostasis in the respiratory and cardiovascular systems depends on reflexes that are initiated at specialized peripheral chemoreceptors that sense changes in the chemical composition of arterial blood. In mammals, the bilaterally-paired carotid bodies (CBs) are the main peripheral chemoreceptor organs that are richly vascularized and are strategically located at the carotid bifurcation. The CBs contribute to the maintenance of O2, CO2/H+, and glucose homeostasis and have attracted much clinical interest because hyperactivity in these organs is associated with several pathophysiological conditions including sleep apnea, obstructive lung disease, heart failure, hypertension, and diabetes. In response to a decrease in O2 availability (hypoxia) and elevated CO2/H+ (acid hypercapnia), CB receptor type I (glomus) cells depolarize and release neurotransmitters that stimulate apposed chemoafferent nerve fibers. The central projections of those fibers in turn activate cardiorespiratory centers in the brainstem, leading to an increase in ventilation and sympathetic drive that helps restore blood PO2 and protect vital organs, e.g., the brain. Significant progress has been made in understanding how neurochemicals released from type I cells such as ATP, adenosine, dopamine, 5-HT, ACh, and angiotensin II help shape the CB afferent discharge during both normal and pathophysiological conditions. However, type I cells typically occur in clusters and in addition to their sensory innervation are ensheathed by the processes of neighboring glial-like, sustentacular type II cells. This morphological arrangement is reminiscent of a "tripartite synapse" and emerging evidence suggests that paracrine stimulation of type II cells by a variety of CB neurochemicals may trigger the release of "gliotransmitters" such as ATP via pannexin-1 channels. Further, recent data suggest novel mechanisms by which dopamine, acting via D2 receptors (D2R), may inhibit action potential firing at petrosal nerve endings. This review will update current ideas concerning the presynaptic and postsynaptic mechanisms that underlie chemosensory processing in the CB. Paracrine signaling pathways will be highlighted, and particularly those that allow the glial-like type II cells to participate in the integrated sensory response during exposures to chemostimuli, including acute and chronic hypoxia.
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Affiliation(s)
- Erin M Leonard
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Shaima Salman
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Colin A Nurse
- Department of Biology, McMaster University, Hamilton, ON, Canada
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16
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Nurse CA, Leonard EM, Salman S. Role of glial-like type II cells as paracrine modulators of carotid body chemoreception. Physiol Genomics 2018. [PMID: 29521602 DOI: 10.1152/physiolgenomics.00142.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Mammalian carotid bodies (CB) are chemosensory organs that mediate compensatory cardiorespiratory reflexes in response to low blood PO2 (hypoxemia) and elevated CO2/H+ (acid hypercapnia). The chemoreceptors are glomus or type I cells that occur in clusters enveloped by neighboring glial-like type II cells. During chemoexcitation type I cells depolarize, leading to Ca2+-dependent release of several neurotransmitters, some excitatory and others inhibitory, that help shape the afferent carotid sinus nerve (CSN) discharge. Among the predominantly excitatory neurotransmitters are the purines ATP and adenosine, whereas dopamine (DA) is inhibitory in most species. There is a consensus that ATP and adenosine, acting via postsynaptic ionotropic P2X2/3 receptors and pre- and/or postsynaptic A2 receptors respectively, are major contributors to the increased CSN discharge during chemoexcitation. However, it has been proposed that the CB sensory output is also tuned by paracrine signaling pathways, involving glial-like type II cells. Indeed, type II cells express functional receptors for several excitatory neurochemicals released by type I cells including ATP, 5-HT, ACh, angiotensin II, and endothelin-1. Stimulation of the corresponding G protein-coupled receptors increases intracellular Ca2+, leading to the further release of ATP through pannexin-1 channels. Recent evidence suggests that other CB neurochemicals, e.g., histamine and DA, may actually inhibit Ca2+ signaling in subpopulations of type II cells. Here, we review evidence supporting neurotransmitter-mediated crosstalk between type I and type II cells of the rat CB. We also consider the potential contribution of paracrine signaling and purinergic catabolic pathways to the integrated sensory output of the CB during chemotransduction.
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Affiliation(s)
- Colin A Nurse
- Department of Biology, McMaster University , Hamilton, Ontario , Canada
| | - Erin M Leonard
- Department of Biology, McMaster University , Hamilton, Ontario , Canada
| | - Shaima Salman
- Department of Biology, McMaster University , Hamilton, Ontario , Canada
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17
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Role of Estradiol Receptor Beta (ERβ) on Arterial Pressure, Respiratory Chemoreflex and Mitochondrial Function in Young and Aged Female Mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1071:115-127. [DOI: 10.1007/978-3-319-91137-3_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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18
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Roach RC, Wagner PD, Ainslie PN, Hackett PH. Translation in Progress: Hypoxia 2017. J Appl Physiol (1985) 2017; 123:922-925. [PMID: 29025903 DOI: 10.1152/japplphysiol.00846.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 11/22/2022] Open
Affiliation(s)
- Robert C Roach
- University of Colorado Altitude Research Center, Department of Medicine, Anschutz Medical Campus, Aurora, Colorado;
| | - Peter D Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Canada; and
| | - Peter H Hackett
- University of Colorado Altitude Research Center, Department of Medicine, Anschutz Medical Campus, Aurora, Colorado.,Institute for Altitude Medicine, Telluride, Colorado
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