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Stocco E, Emmi A, Sfriso MM, Tushevski A, De Caro R, Macchi V, Porzionato A. Carotid body plastic behavior: evidence for D 2-H 3 receptor-receptor interactions. Front Physiol 2024; 15:1422270. [PMID: 39072219 PMCID: PMC11272601 DOI: 10.3389/fphys.2024.1422270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 06/24/2024] [Indexed: 07/30/2024] Open
Abstract
Dopamine and histamine receptors D2R and H3R are G protein-coupled receptors (GPCRs) which can establish physical receptor-receptor interactions (RRIs), leading to homo/hetero-complexes in a dynamic equilibrium. Although D2R and H3R expression has been detected within the carotid body (CB), their possible heterodimerization has never been demonstrated. The aim of this work was to verify D2R and H3R colocalization in the CB, thus suggesting a possible interplay that, in turn, may be responsible of specific D2R-H3R antagonistic functional implications. The CBs of both Sprague-Dawley rats (n = 5) and human donors (n = 5) were dissected, and immunolocalization of D2R and H3R was performed; thereafter, in situ proximity ligation assay (PLA) was developed. According to experimental evidence (immunohistochemistry and double immunofluorescence), all the samples displayed positive D2R/H3R elements; hence, PLA assay followed by confocal microscopy analysis was positive for D2R-H3R RRIs. Additionally, D2R-H3R heterodimers were mainly detected in type I cells (βIII-tubulin-positive cells), but type II cells' involvement cannot be excluded. RRIs may play a role in functional modulation of CB cells; investigating RRIs in the CB may guide toward the comprehension of its plastic changes and fine regulatory role while also unveiling their possible clinical implications.
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Affiliation(s)
- Elena Stocco
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
- Department of Women’s and Children’s Health, University of Padova, Padua, Italy
- Department of Surgery, Oncology and Gastroenterology, University of Padova, Padua, Italy
| | - Aron Emmi
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
| | - Maria Martina Sfriso
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
| | - Aleksandar Tushevski
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
| | - Raffaele De Caro
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
| | - Veronica Macchi
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
| | - Andrea Porzionato
- Section of Human Anatomy, Department of Neuroscience, University of Padova, Padua, Italy
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Getsy PM, Coffee GA, Hsieh YH, Lewis SJ. Loss of Cervical Sympathetic Chain Input to the Superior Cervical Ganglia Affects the Ventilatory Responses to Hypoxic Challenge in Freely-Moving C57BL6 Mice. Front Physiol 2021; 12:619688. [PMID: 33967819 PMCID: PMC8100345 DOI: 10.3389/fphys.2021.619688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
The cervical sympathetic chain (CSC) innervates post-ganglionic sympathetic neurons within the ipsilateral superior cervical ganglion (SCG) of all mammalian species studied to date. The post-ganglionic neurons within the SCG project to a wide variety of structures, including the brain (parenchyma and cerebral arteries), upper airway (e.g., nasopharynx and tongue) and submandibular glands. The SCG also sends post-ganglionic fibers to the carotid body (e.g., chemosensitive glomus cells and microcirculation), however, the function of these connections are not established in the mouse. In addition, nothing is known about the functional importance of the CSC-SCG complex (including input to the carotid body) in the mouse. The objective of this study was to determine the effects of bilateral transection of the CSC on the ventilatory responses [e.g., increases in frequency of breathing (Freq), tidal volume (TV) and minute ventilation (MV)] that occur during and following exposure to a hypoxic gas challenge (10% O2 and 90% N2) in freely-moving sham-operated (SHAM) adult male C57BL6 mice, and in mice in which both CSC were transected (CSCX). Resting ventilatory parameters (19 directly recorded or calculated parameters) were similar in the SHAM and CSCX mice. There were numerous important differences in the responses of CSCX and SHAM mice to the hypoxic challenge. For example, the increases in Freq (and associated decreases in inspiratory and expiratory times, end expiratory pause, and relaxation time), and the increases in MV, expiratory drive, and expiratory flow at 50% exhaled TV (EF50) occurred more quickly in the CSCX mice than in the SHAM mice, although the overall responses were similar in both groups. Moreover, the initial and total increases in peak inspiratory flow were higher in the CSCX mice. Additionally, the overall increases in TV during the latter half of the hypoxic challenge were greater in the CSCX mice. The ventilatory responses that occurred upon return to room-air were essentially similar in the SHAM and CSCX mice. Overall, this novel data suggest that the CSC may normally provide inhibitory input to peripheral (e.g., carotid bodies) and central (e.g., brainstem) structures that are involved in the ventilatory responses to hypoxic gas challenge in C57BL6 mice.
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Affiliation(s)
- Paulina M Getsy
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States.,The Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Gregory A Coffee
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen J Lewis
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States
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Wakai J, Takayama A, Yokoyama T, Nakamuta N, Kusakabe T, Yamamoto Y. Immunohistochemical localization of dopamine D2 receptor in the rat carotid body. Acta Histochem 2015; 117:784-9. [PMID: 26272445 DOI: 10.1016/j.acthis.2015.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/31/2015] [Accepted: 07/31/2015] [Indexed: 10/23/2022]
Abstract
Dopamine modulates the chemosensitivity of arterial chemoreceptors, and dopamine D2 receptor (D2R) is expected to localize in the glomus cells and/or sensory nerve endings of the carotid body. In the present study, the localization of D2R in the rat carotid body was examined using double immunofluorescence for D2R with various cell markers. D2R immunoreactivity was mainly localized in glomus cells immunoreactive to tyrosine hydroxylase or dopamine β-hydroxylase (DBH), but not in S100B-immunoreactive sustentacular cells. Furthermore, D2R immunoreactivity was observed in petrosal ganglion cells and nerve bundles in the carotid body, but not in the nerve endings with P2X2 immunoreactivity. In the carotid ganglion, a few punctate D2R-immunoreactive products were detected in DBH-immunoreactive nerve cell bodies. These results showed that D2R was mainly distributed in glomus cells, and suggested that D2R plays a role in the inhibitory modulation of chemosensory activity in a paracrine and/or autocrine manner.
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Nunes AR, Holmes AP, Conde SV, Gauda EB, Monteiro EC. Revisiting cAMP signaling in the carotid body. Front Physiol 2014; 5:406. [PMID: 25389406 PMCID: PMC4211388 DOI: 10.3389/fphys.2014.00406] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 10/01/2014] [Indexed: 12/25/2022] Open
Abstract
Chronic carotid body (CB) activation is now recognized as being essential in the development of hypertension and promoting insulin resistance; thus, it is imperative to characterize the chemotransduction mechanisms of this organ in order to modulate its activity and improve patient outcomes. For several years, and although controversial, cyclic adenosine monophosphate (cAMP) was considered an important player in initiating the activation of the CB. However, its relevance was partially displaced in the 90s by the emerging role of the mitochondria and molecules such as AMP-activated protein kinase and O2-sensitive K+ channels. Neurotransmitters/neuromodulators binding to metabotropic receptors are essential to chemotransmission in the CB, and cAMP is central to this process. cAMP also contributes to raise intracellular Ca2+ levels, and is intimately related to the cellular energetic status (AMP/ATP ratio). Furthermore, cAMP signaling is a target of multiple current pharmacological agents used in clinical practice. This review (1) provides an outline on the classical view of the cAMP-signaling pathway in the CB that originally supported its role in the O2/CO2 sensing mechanism, (2) presents recent evidence on CB cAMP neuromodulation and (3) discusses how CB activity is affected by current clinical therapies that modify cAMP-signaling, namely dopaminergic drugs, caffeine (modulation of A2A/A2B receptors) and roflumilast (PDE4 inhibitors). cAMP is key to any process that involves metabotropic receptors and the intracellular pathways involved in CB disease states are likely to involve this classical second messenger. Research examining the potential modification of cAMP levels and/or interactions with molecules associated with CB hyperactivity is currently in its beginning and this review will open doors for future explorations.
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Affiliation(s)
- Ana R Nunes
- CEDOC, Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa Lisboa, Portugal
| | - Andrew P Holmes
- School of Clinical and Experimental Medicine, University of Birmingham Birmingham, UK
| | - Sílvia V Conde
- CEDOC, Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa Lisboa, Portugal
| | - Estelle B Gauda
- Neonatology Research Laboratories, Department of Pediatrics, Johns Hopkins Medical Institutions, Johns Hopkins University Baltimore, MD, USA
| | - Emília C Monteiro
- CEDOC, Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa Lisboa, Portugal
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Kåhlin J, Mkrtchian S, Ebberyd A, Hammarstedt-Nordenvall L, Nordlander B, Yoshitake T, Kehr J, Prabhakar N, Poellinger L, Fagerlund MJ, Eriksson LI. The human carotid body releases acetylcholine, ATP and cytokines during hypoxia. Exp Physiol 2014; 99:1089-98. [PMID: 24887113 DOI: 10.1113/expphysiol.2014.078873] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Studies on experimental animals established that the carotid bodies are sensory organs for detecting arterial blood O2 levels and that the ensuing chemosensory reflex is a major regulator of cardiorespiratory functions during hypoxia. However, little information is available on the human carotid body responses to hypoxia. The present study was performed on human carotid bodies obtained from surgical patients undergoing elective head and neck cancer surgery. Our results show that exposing carotid body slices to hypoxia for a period as brief as 5 min markedly facilitates the release of ACh and ATP. Furthermore, prolonged hypoxia for 1 h induces an increased release of interleukin (IL)-1β, IL-4, IL-6, IL-8 and IL-10. Immunohistochemical analysis revealed that type 1 cells of the human carotid body express an array of cytokine receptors as well as hypoxia-inducible factor-1α and hypoxia-inducible factor-2α. Taken together, these results demonstrate that ACh and ATP are released from the human carotid body in response to hypoxia, suggesting that these neurotransmitters, as in several experimental animal models, play a role in hypoxic signalling also in the human carotid body. The finding that the human carotid body releases cytokines in response to hypoxia adds to the growing body of information suggesting that the carotid body may play a role in detecting inflammation, providing a link between the immune system and the nervous system.
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Affiliation(s)
- Jessica Kåhlin
- Section for Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden Department of Anesthesiology, Surgical Services and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
| | - Souren Mkrtchian
- Section for Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Anette Ebberyd
- Section for Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | | | - Britt Nordlander
- Department of Otorhinolaryngology (ENT), Karolinska University Hospital, Stockholm, Sweden
| | - Takashi Yoshitake
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jan Kehr
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Nanduri Prabhakar
- Institute for Integrative Physiology & Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Lorenz Poellinger
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Malin Jonsson Fagerlund
- Section for Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden Department of Anesthesiology, Surgical Services and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
| | - Lars I Eriksson
- Section for Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden Department of Anesthesiology, Surgical Services and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
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De Caro R, Macchi V, Sfriso MM, Porzionato A. Structural and neurochemical changes in the maturation of the carotid body. Respir Physiol Neurobiol 2013; 185:9-19. [DOI: 10.1016/j.resp.2012.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 05/16/2012] [Accepted: 06/08/2012] [Indexed: 02/07/2023]
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Mkrtchian S, Kåhlin J, Ebberyd A, Gonzalez C, Sanchez D, Balbir A, Kostuk EW, Shirahata M, Fagerlund MJ, Eriksson LI. The human carotid body transcriptome with focus on oxygen sensing and inflammation--a comparative analysis. J Physiol 2012; 590:3807-19. [PMID: 22615433 DOI: 10.1113/jphysiol.2012.231084] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The carotid body (CB) is the key oxygen sensing organ. While the expression of CB specific genes is relatively well studied in animals, corresponding data for the human CB are missing. In this study we used five surgically removed human CBs to characterize the CB transcriptome with microarray and PCR analyses, and compared the results with mice data. In silico approaches demonstrated a unique gene expression profile of the human and mouse CB transcriptomes and an unexpected upregulation of both human and mouse CB genes involved in the inflammatory response compared to brain and adrenal gland data. Human CBs express most of the genes previously proposed to be involved in oxygen sensing and signalling based on animal studies, including NOX2, AMPK, CSE and oxygen sensitive K+ channels. In the TASK subfamily of K+ channels, TASK-1 is expressed in human CBs, while TASK-3 and TASK-5 are absent, although we demonstrated both TASK-1 and TASK-3 in one of the mouse reference strains. Maxi-K was expressed exclusively as the spliced variant ZERO in the human CB. In summary, the human CB transcriptome shares important features with the mouse CB, but also differs significantly in the expression of a number of CB chemosensory genes. This study provides key information for future functional investigations on the human carotid body.
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Affiliation(s)
- Souren Mkrtchian
- Section for Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
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Lalley PM, Mifflin SW. Opposing effects on the phrenic motor pathway attributed to dopamine-D1 and -D3/D2 receptor activation. Respir Physiol Neurobiol 2012; 181:183-93. [PMID: 22465544 DOI: 10.1016/j.resp.2012.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/09/2012] [Accepted: 03/12/2012] [Indexed: 01/11/2023]
Abstract
Previous in vivo studies revealed that dopamine-D1-agonists elevate excitability of ventral respiratory column (VRC) neurons and increase discharge activity in the phrenic motor output through actions in the brainstem. In this in vivo study performed on pentobarbital-anesthetized cats, we show that D1-agonists (SKF-38393, dihydrexidine) given intravenously enhanced discharge activity in VRC inspiratory neurons and the phrenic nerve in two stages; discharge intensity first increased to a peak and then discharge duration increased. Cross-correlation analysis of VRC inspiratory neuron and phrenic nerve discharges showed that both stages increased strength of coupling between medullary inspiratory neurons and the phrenic motoneuron output. Intracellular recording and microiontophoresis experiments indicated that D1-agonists produced their stimulatory effects indirectly through actions on synaptic inputs to VRC inspiratory neurons. Because other laboratories have provided evidence that dopamine acting on other types of receptors depresses respiratory neuron excitability we tested the effects of piribedil, an agonist that activates receptors of the generally depressant D3/D2-dopamine receptor family, on phrenic nerve activity. Piribedil depressed phrenic nerve inspiratory discharge intensity, prolonged discharge duration, slowed burst frequency and slowed rate of action potential augmentation. The effects of piribedil were partially counteracted by intravenous injection of dihydrexidine. We propose that under normal, steady state conditions, D1-receptor-mediated excitatory modulation of phrenic motor output overrides D3/D2-receptor mediated inhibition.
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Affiliation(s)
- Peter M Lalley
- The University of Wisconsin Medical Sciences Center, United States
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Meza RC, Ortiz FC, Bravo E, Iturriaga-Vásquez P, Eugenín JL, Varas R. Functional expression of the α7 and α4-containing nicotinic acetylcholine receptors on the neonatal rat carotid body. Neurochem Int 2012; 60:115-24. [DOI: 10.1016/j.neuint.2011.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 09/13/2011] [Accepted: 11/15/2011] [Indexed: 01/02/2023]
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Abstract
The discovery of the sensory nature of the carotid body dates back to the beginning of the 20th century. Following these seminal discoveries, research into carotid body mechanisms moved forward progressively through the 20th century, with many descriptions of the ultrastructure of the organ and stimulus-response measurements at the level of the whole organ. The later part of 20th century witnessed the first descriptions of the cellular responses and electrophysiology of isolated and cultured type I and type II cells, and there now exist a number of testable hypotheses of chemotransduction. The goal of this article is to provide a comprehensive review of current concepts on sensory transduction and transmission of the hypoxic stimulus at the carotid body with an emphasis on integrating cellular mechanisms with the whole organ responses and highlighting the gaps or discrepancies in our knowledge. It is increasingly evident that in addition to hypoxia, the carotid body responds to a wide variety of blood-borne stimuli, including reduced glucose and immune-related cytokines and we therefore also consider the evidence for a polymodal function of the carotid body and its implications. It is clear that the sensory function of the carotid body exhibits considerable plasticity in response to the chronic perturbations in environmental O2 that is associated with many physiological and pathological conditions. The mechanisms and consequences of carotid body plasticity in health and disease are discussed in the final sections of this article.
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Affiliation(s)
- Prem Kumar
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, United Kingdom.
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Wotzlaw C, Bernardini A, Berchner-Pfannschmidt U, Papkovsky D, Acker H, Fandrey J. Multifocal animated imaging of changes in cellular oxygen and calcium concentrations and membrane potential within the intact adult mouse carotid body ex vivo. Am J Physiol Cell Physiol 2011; 301:C266-71. [DOI: 10.1152/ajpcell.00508.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Carotid body (CB) type I cell hypoxia-sensing function is assumed to be based on potassium channel inhibition. Subsequent membrane depolarization initiates an intracellular calcium increase followed by transmitter release for excitation of synapses with linked nerve endings. Several reports, however, contradict this generally accepted concept by showing that type I cell oxygen-sensing properties vary significantly depending on the method of their isolation. We report therefore for the first time noninvasive mapping of the oxygen-sensing properties of type I cells within the intact adult mouse CB ex vivo by using multifocal Nipkow disk-based imaging of oxygen-, calcium- and potential-sensitive cellular dyes. Characteristic type I cell clusters were identified in the compact tissue by immunohistochemistry because of their large cell nuclei combined with positive tyrosine hydroxylase staining. The cellular calcium concentrations in these cell clusters either increased or decreased in response to reduced tissue oxygen concentrations. Under control conditions, cellular potential oscillations were uniform at ∼0.02 Hz. Under hypoxia-induced membrane depolarization, these oscillations ceased. Simultaneous increases and decreases in potential of these cell clusters resulted from spontaneous burstlike activities lasting ∼1.5 s. type I cells, identified during the experiments by cluster formation in combination with large cell nuclei, seem to respond to hypoxia with heterogeneous kinetics.
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Affiliation(s)
- Christoph Wotzlaw
- Department of Physiology, University of Duisburg-Essen, Essen, Germany; and
| | - André Bernardini
- Department of Physiology, University of Duisburg-Essen, Essen, Germany; and
| | | | | | - Helmut Acker
- Department of Physiology, University of Duisburg-Essen, Essen, Germany; and
| | - Joachim Fandrey
- Department of Physiology, University of Duisburg-Essen, Essen, Germany; and
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Teppema LJ, Baby S. Anesthetics and control of breathing. Respir Physiol Neurobiol 2011; 177:80-92. [PMID: 21514403 DOI: 10.1016/j.resp.2011.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 04/04/2011] [Accepted: 04/07/2011] [Indexed: 12/18/2022]
Abstract
An important side effect of general anesthetics is respiratory depression. Anesthetics have multiple membrane targets of which ionotropic receptors such as gamma-aminobutyric acid-A (GABA(A)), glycine, N-methyl-D-aspartate and nicotinic acetylcholinergic (nACh) receptors are important members. GABA, glutamate and ACh are crucial neurotransmitters in the respiratory neuronal network, and the ability of anesthetics to modulate their release and interact with their receptors implies complex effects on respiration. Metabotropic receptors and intracellular proteins are other important targets for anesthetics suggesting complex effects on intracellular signaling pathways. Here we briefly overview the effects of general anesthetics on protein targets as far as these are relevant for respiratory control. Subsequently, we describe some methods with which the overall effect of anesthetics on the control of breathing can be measured, as well as some promising in vivo approaches to study their synaptic effects. Finally, we summarize the most important respiratory effects of volatile anesthetics in humans and animals and those of some intravenous anesthetics in animals.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands.
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Wakai J, Kizaki K, Yamaguchi-Yamada M, Yamamoto Y. Differences in tyrosine hydroxylase expression after short-term hypoxia, hypercapnia or hypercapnic hypoxia in rat carotid body. Respir Physiol Neurobiol 2010; 173:95-100. [PMID: 20620242 DOI: 10.1016/j.resp.2010.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 06/29/2010] [Accepted: 07/01/2010] [Indexed: 12/22/2022]
Abstract
In the carotid body (CB), it has been reported that the expressions of tyrosine hydroxylase (TH) mRNA and TH protein are enhanced by exposure to hypoxia. However, it is not known whether CO(2) affects the expression of TH in the CB. We examined the expression of TH mRNA and the immunoreactivity for TH in the CB of rats exposed to hypoxia (10% O(2)), hypercapnia (10% CO(2)) and hypercapnic hypoxia (10% O(2) and 10% CO(2)) for 2-24 h. The expression of TH mRNA in the CB was markedly enhanced in rats exposed to hypoxia for 4 h (6.6-fold), 6 h (6.0-fold) and 8 h (7.8-fold), and in rats exposed to hypercapnic hypoxia for 12 h (4.8-fold). The most intense TH immunoreactivity was observed in the CB from rats exposed to hypoxia for 12 and 24 h and to hypercapnic hypoxia for 24 h. The expressions of TH mRNA and the immunoreactivity for TH were not altered in the CB of rats exposed to hypercapnia. It is suggested that CO(2) does not affect TH expression in the CB, and that it inhibits hypoxia-enhanced TH expression.
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Affiliation(s)
- Jun Wakai
- Laboratory of Veterinary Biochemistry and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan
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