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Hao X, Yang Y, Liu J, Zhang D, Ou M, Ke B, Zhu T, Zhou C. The Modulation by Anesthetics and Analgesics of Respiratory Rhythm in the Nervous System. Curr Neuropharmacol 2024; 22:217-240. [PMID: 37563812 PMCID: PMC10788885 DOI: 10.2174/1570159x21666230810110901] [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: 11/23/2022] [Revised: 04/27/2023] [Accepted: 02/28/2023] [Indexed: 08/12/2023] Open
Abstract
Rhythmic eupneic breathing in mammals depends on the coordinated activities of the neural system that sends cranial and spinal motor outputs to respiratory muscles. These outputs modulate lung ventilation and adjust respiratory airflow, which depends on the upper airway patency and ventilatory musculature. Anesthetics are widely used in clinical practice worldwide. In addition to clinically necessary pharmacological effects, respiratory depression is a critical side effect induced by most general anesthetics. Therefore, understanding how general anesthetics modulate the respiratory system is important for the development of safer general anesthetics. Currently used volatile anesthetics and most intravenous anesthetics induce inhibitory effects on respiratory outputs. Various general anesthetics produce differential effects on respiratory characteristics, including the respiratory rate, tidal volume, airway resistance, and ventilatory response. At the cellular and molecular levels, the mechanisms underlying anesthetic-induced breathing depression mainly include modulation of synaptic transmission of ligand-gated ionotropic receptors (e.g., γ-aminobutyric acid, N-methyl-D-aspartate, and nicotinic acetylcholine receptors) and ion channels (e.g., voltage-gated sodium, calcium, and potassium channels, two-pore domain potassium channels, and sodium leak channels), which affect neuronal firing in brainstem respiratory and peripheral chemoreceptor areas. The present review comprehensively summarizes the modulation of the respiratory system by clinically used general anesthetics, including the effects at the molecular, cellular, anatomic, and behavioral levels. Specifically, analgesics, such as opioids, which cause respiratory depression and the "opioid crisis", are discussed. Finally, underlying strategies of respiratory stimulation that target general anesthetics and/or analgesics are summarized.
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Affiliation(s)
- Xuechao Hao
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yaoxin Yang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Mengchan Ou
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Bowen Ke
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
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Montaño LM, Flores-Soto E, Sommer B, Solís-Chagoyán H, Perusquía M. Androgens are effective bronchodilators with anti-inflammatory properties: A potential alternative for asthma therapy. Steroids 2020; 153:108509. [PMID: 31586608 DOI: 10.1016/j.steroids.2019.108509] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 09/17/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022]
Abstract
Changes in plasma androgen levels in asthmatic men may be linked to asthma severity, seemingly acting through nongenomic and genomic effects. Nongenomic effects include rapid relaxation of carbachol or antigenic challenge pre-contracted guinea pig airway smooth muscle (ASM) in vitro: testosterone (TES) blocks l-type voltage dependent Ca2+ channels, stored operated Ca2+ channels, inositol 1,4,5-trisphosphate receptors and promotes prostaglandin E2 biosynthesis. In ASM at rest, TES lowers basal intracellular Ca2+ concentration and tension, maintaining a proper airway patency keeping steady smooth muscle tension and basal intracellular Ca2+ concentration at rest. Moreover, the bronchospasm in sensitized guinea-pigs was ablated by dehydroepiandrosterone (DHEA), a precursor of steroids, TES and its metabolites 5α- and 5β-dihydrotestosterone (DHT). On the other hand, genomic effects related to androgens' anti-inflammatory properties in asthma have been recently studied. Briefly, TES negatively regulates type 2 immune response sustained by CD4+ Th2 and group 2 innate lymphoid cells, diminishing allergic airway inflammation in males. Also, novel findings establish that TES decreases interleukin (IL)-17A protein expression produced by CD4+ Th17 cells and therefore neutrophilic airway inflammation. Clearly, DHEA, TES or its 5β-reduced metabolite that possesses minimal androgenic effect, might have potential therapeutic capacities in the treatment of severe asthma via mechanisms distinct from corticosteroid treatment.
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Affiliation(s)
- Luis M Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, CDMX, Mexico.
| | - Edgar Flores-Soto
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, CDMX, Mexico.
| | - Bettina Sommer
- Departamento de Investigación en Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, CDMX, Mexico.
| | - Héctor Solís-Chagoyán
- Laboratorio de Neurofarmacología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, CDMX, Mexico.
| | - Mercedes Perusquía
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CDMX, Mexico.
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Reyes-García J, Flores-Soto E, Carbajal-García A, Sommer B, Montaño LM. Maintenance of intracellular Ca2+ basal concentration in airway smooth muscle (Review). Int J Mol Med 2018; 42:2998-3008. [PMID: 30280184 PMCID: PMC6202086 DOI: 10.3892/ijmm.2018.3910] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 09/18/2018] [Indexed: 01/07/2023] Open
Abstract
In airway smooth muscle, the intracellular basal Ca2+ concentration [b(Ca2+)i] must be tightly regulated by several mechanisms in order to maintain a proper airway patency. The b[Ca2+]i is efficiently regulated by sarcoplasmic reticulum Ca2+-ATPase 2b, plasma membrane Ca2+-ATPase 1 or 4 and by the Na+/Ca2+ exchanger. Membranal Ca2+ channels, including the L-type voltage dependent Ca2+ channel (L-VDCC), T-type voltage dependent Ca2+ channel (T-VDCC) and transient receptor potential canonical 3 (TRPC3), appear to be constitutively active under basal conditions via the action of different signaling pathways, and are responsible for Ca2+ influx to maintain b[Ca2+]i. The two types of voltage-dependent Ca2+ channels (L- and T-type) are modulated by phosphorylation processes mediated by mitogen-activated protein kinase kinase (MEK) and extracellular-signal-regulated kinase 1 and 2 (ERK1/2). The MEK/ERK signaling pathway can be activated by G-protein-coupled receptors through the αq subunit when the endogenous ligand (i.e., acetylcholine, histamine, leukotrienes, etc.) is present under basal conditions. It may also be stimulated when receptor tyrosine kinases are occupied by the appropriate ligand (cytokines, growth factors, etc.). ERK1/2 phosphorylates L-VDCC on Ser496 of the β2 subunit and Ser1928 of the α1 subunit, decreasing or increasing the channel activity, respectively, and enabling it to switch between an open and closed state. T-VDCC is also probably phosphorylated by ERK1/2, although further research is required to identify the phosphorylation sites. TRPC3 is directly activated by diacylglycerol produced by phospholipase C (PLCβ or γ). Constitutive inositol 1,4,5-trisphosphate production induces the release of Ca2+ from the sarcoplasmic reticulum through inositol triphosphate receptor 1. This ion induces Ca2+-induced Ca2+ release through the ryanodine receptor 2 (designated as Ca2+ ‘sparks’). Therefore, several Ca2+ handling mechanisms are finely tuned to regulate basal intracellular Ca2+ concentrations. It is conceivable that alterations in any of these processes may render airway smooth muscle susceptible to develop hyperresponsiveness that is observed in ailments such as asthma.
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Affiliation(s)
- Jorge Reyes-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Edgar Flores-Soto
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Abril Carbajal-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Bettina Sommer
- Departamento de Investigación en Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias, Ciudad de México 14080, México
| | - Luis M Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
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Keeler AM, Liu D, Zieger M, Xiong L, Salemi J, Bellvé K, Byrne BJ, Fuller DD, ZhuGe R, ElMallah MK. Airway smooth muscle dysfunction in Pompe ( Gaa-/- ) mice. Am J Physiol Lung Cell Mol Physiol 2017; 312:L873-L881. [PMID: 28336814 DOI: 10.1152/ajplung.00568.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/20/2017] [Accepted: 03/20/2017] [Indexed: 01/01/2023] Open
Abstract
Pompe disease is an autosomal recessive disorder caused by a deficiency of acid α-glucosidase (GAA), an enzyme responsible for hydrolyzing lysosomal glycogen. Deficiency of GAA leads to systemic glycogen accumulation in the lysosomes of skeletal muscle, motor neurons, and smooth muscle. Skeletal muscle and motor neuron pathology are known to contribute to respiratory insufficiency in Pompe disease, but the role of airway pathology has not been evaluated. Here we propose that GAA enzyme deficiency disrupts the function of the trachea and bronchi and this lower airway pathology contributes to respiratory insufficiency in Pompe disease. Using an established mouse model of Pompe disease, the Gaa-/- mouse, we compared histology, pulmonary mechanics, airway smooth muscle (ASM) function, and calcium signaling between Gaa-/- and age-matched wild-type (WT) mice. Lysosomal glycogen accumulation was observed in the smooth muscle of both the bronchi and the trachea in Gaa-/- but not WT mice. Furthermore, Gaa-/- mice had hyporesponsive airway resistance and bronchial ring contraction to the bronchoconstrictive agents methacholine (MCh) and potassium chloride (KCl) and to a bronchodilator (albuterol). Finally, calcium signaling during bronchiolar smooth muscle contraction was impaired in Gaa-/- mice indicating impaired extracellular calcium influx. We conclude that GAA enzyme deficiency leads to glycogen accumulation in the trachea and bronchi and impairs the ability of lower ASM to regulate calcium and respond appropriately to bronchodilator or constrictors. Accordingly, ASM dysfunction may contribute to respiratory impairments in Pompe disease.
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Affiliation(s)
- Allison M Keeler
- Division of Pulmonary Medicine, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts.,Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Donghai Liu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Marina Zieger
- Division of Pulmonary Medicine, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts.,Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Lang Xiong
- Division of Pulmonary Medicine, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts.,Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jeffrey Salemi
- Division of Pulmonary Medicine, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts.,Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Karl Bellvé
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Barry J Byrne
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida, Gainesville, Florida; and
| | - David D Fuller
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Ronghua ZhuGe
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Mai K ElMallah
- Division of Pulmonary Medicine, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts; .,Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts
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Flores-Soto E, Reyes-García J, Carbajal-García A, Campuzano-González E, Perusquía M, Sommer B, Montaño LM. Sex steroids effects on guinea pig airway smooth muscle tone and intracellular Ca 2+ basal levels. Mol Cell Endocrinol 2017; 439:444-456. [PMID: 27717744 DOI: 10.1016/j.mce.2016.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/06/2016] [Accepted: 10/03/2016] [Indexed: 02/07/2023]
Abstract
UNLABELLED Testosterone (TES), other androgens and female sex steroids induce non-genomic rapid relaxing effects in airway smooth muscle (ASM). In guinea pig ASM, basal tension was relaxed by dehydroepiandrosterone (DHEA) and TES; 17β-estradiol (E2) had a small effect. Blockers of L-type voltage dependent Ca2+ channel (L-VDCC, D-600) and store operated Ca2+ channel (SOC, 2-APB) also relaxed the basal tone. In tracheal myocytes, DHEA and TES diminished intracellular basal Ca2+ concentrations (b[Ca2+]i) as D-600+2-APB but to a higher extend. TES after D-600+2APB or Pyr3, a blocker of canonical transient receptor potential 3 (TRPC3), further decreased b[Ca2+]i rendering this response equal to TES alone. With indomethacin, the b[Ca2+]i decrease induced by the blockade of L-VDCC and TRPC3 was not changed by the addition of TES. PGE2 or forskolin addition after D600+2-APB, decreased b[Ca2+]i resembling TES response. An adenylate cyclase inhibitor followed by D-600+2-APB lowered b[Ca2+]i, TES showed no further effect. Carbachol-induced [Ca2+]i increment was reduced by TES or DHEA. 17β-estradiol diminished KCl-induced contraction and, in tracheal myocytes, the voltage-dependent inward Ca2+ current. CONCLUSION DHEA and TES diminish ASM tone and b[Ca2+]i by blocking L-VDCC and probably a constitutively active TRPC3, and by PGE2 synthesis. E2 lowers ASM basal tone by blocking only L-VDCC.
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Affiliation(s)
- Edgar Flores-Soto
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Jorge Reyes-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Abril Carbajal-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Elías Campuzano-González
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Mercedes Perusquía
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Bettina Sommer
- Departamento de Investigación en Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias, 14080, Ciudad de México, Mexico
| | - Luis M Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico.
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Wylam ME, Xue A, Sieck GC. Mechanisms of intrinsic force in small human airways. Respir Physiol Neurobiol 2012; 181:99-108. [PMID: 22322114 DOI: 10.1016/j.resp.2012.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 10/14/2022]
Abstract
We quantified the magnitude and investigated mechanisms regulating intrinsic force (IF) in human airway smooth muscle (hASM). IF was identified by reducing extracellular calcium (Ca2+) concentration to nominally zero in freshly isolated isometrically mounted 2mm human bronchi. Our results show: (1) the magnitude of IF is ∼50% of the maximal total force elicited by acetylcholine (10(-5) M) and is epithelial independent, (2) IF can also be revealed by β-adrenergic activation (isoproterenol), non-specific cationic channel blockade (La3+) or L-type voltage gated Ca2+ channel blockade (nifedipine), (3) atropine, indomethacin, AA-861, or pyrilamine did not affect IF, (4) IF was reduced by the intracellular Ca2+ ([Ca2+]i) chelating agent BAPTA-AM, (5) ω-conotoxin had no effect on IF. In studies in cultured hASM cells nominally zero Ca2+ buffer and BAPTA-AM reduced [Ca2+]i but isoproterenol and nifedipine did not. Taken together these results indicate that rapid reduction of [Ca2+]i reveals a permissive relationship between extracellular Ca2+, [Ca2+]i and IF. However IF can be dissipated by mechanisms effecting Ca2+ sensitivity. We speculate that an increase of IF, a fundamental property of ASM, could be related to human airway clinical hyperresponsiveness and must be accounted for in in vitro studies of hASM.
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Affiliation(s)
- Mark E Wylam
- Division of Pulmonary and Critical Care Medicine, Departments of Medicine, Pediatrics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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cGMP reduces the sarcoplasmic reticulum Ca2+ loading in airway smooth muscle cells: a putative mechanism in the regulation of Ca2+ by cGMP. J Muscle Res Cell Motil 2011; 32:375-82. [PMID: 21997642 DOI: 10.1007/s10974-011-9266-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 09/30/2011] [Indexed: 10/17/2022]
Abstract
Ca(2+) and cGMP have opposite roles in many physiological processes likely due to a complex negative feedback regulation between them. Examples of opposite functions induced by Ca(2+) and cGMP are smooth muscle contraction and relaxation, respectively. A main Ca(2+) storage involved in contraction is sarcoplasmic reticulum (SR); nevertheless, the role of cGMP in the regulation of SR-Ca(2+) has not been completely understood. To evaluate this role, intracellular Ca(2+) concentration ([Ca(2+)]i) was determinated by a ratiometric method in isolated myocytes from bovine trachea incubated with Fura-2/AM. The release of Ca(2+) from SR induced by caffeine was transient, whereas caffeine withdrawal was followed by a [Ca(2+)]i undershoot. Caffeine-induced Ca(2+) transient peak and [Ca(2+)]i undershoot after caffeine were reproducible in the same cell. Dibutyryl cGMP (db-cGMP) blocked the [Ca(2+)]i undershoot and reduced the subsequent caffeine peak (SR-Ca(2+) loading). Both, the opening of SR channels with ryanodine (10 μM) and the blockade of SR-Ca(2+) ATPase with cyclopiazonic acid inhibited the [Ca(2+)]i undershoot as well as the SR-Ca(2+) loading. The addition of db-cGMP to ryanodine (10 μM) incubated cells partially restored the SR-Ca(2+) loading. Cyclic GMP enhanced [Ca(2+)]i undershoot induced by the blockade of ryanodine channels with 50 μM ryanodine. In conclusion, the reduction of SR-Ca(2+) content in airway smooth muscle induced by cGMP can be explained by the combination of SR-Ca(2+) loading and the simultaneous release of SR-Ca(2+). The reduction of SR-Ca(2+) content induced by cGMP might be a putative mechanism limiting releasable Ca(2+) in response to a particular stimulus.
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Chávez J, Vargas MH, Cruz-Valderrama JE, Montaño LM. Non-quantal release of acetylcholine in guinea-pig airways: role of choline transporter. Exp Physiol 2011; 96:460-7. [DOI: 10.1113/expphysiol.2010.056440] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mizuta K, Gallos G, Zhu D, Mizuta F, Goubaeva F, Xu D, Panettieri RA, Yang J, Emala CW. Expression and coupling of neurokinin receptor subtypes to inositol phosphate and calcium signaling pathways in human airway smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2008; 294:L523-34. [PMID: 18203813 DOI: 10.1152/ajplung.00328.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Neuropeptide tachykinins (substance P, neurokinin A, and neurokinin B) are present in peripheral terminals of sensory nerve fibers within the respiratory tract and cause airway contractile responses and hyperresponsiveness in humans and most mammalian species. Three subtypes of neurokinin receptors (NK1R, NK2R, and NK3R) classically couple to Gq protein-mediated inositol 1,4,5-trisphosphate (IP3) synthesis and liberation of intracellular Ca2+, which initiates contraction, but their expression and calcium signaling mechanisms are incompletely understood in airway smooth muscle. All three subtypes were identified in native and cultured human airway smooth muscle (HASM) and were subsequently overexpressed in HASM cells using a human immunodeficiency virus-1-based lentivirus transduction system. Specific NKR agonists {NK1R, [Sar9,Met(O2)11]-substance P; NK2R, [beta-Ala8]-neurokinin A(4-10); NK3R, senktide} stimulated inositol phosphate synthesis and increased intracellular Ca2+ concentration ([Ca2+]i) in native HASM cells and in HASM cells transfected with each NKR subtype. These effects were blocked by NKR-selective antagonists (NK1R, L-732138; NK2R, GR-159897; NK3R, SB-222200). The initial transient and sustained phases of increased [Ca2+]i were predominantly inhibited by the IP3 receptor antagonist 2-aminoethoxydiphenyl borate (2-APB) or the store-operated Ca2+ channel antagonist SKF-96365, respectively. These results show that all three subtypes of NKRs are expressed in native HASM cells and that IP3 levels are the primary mediators of NKR-stimulated initial [Ca2+]i increases, whereas store-operated Ca2+ channels mediate the sustained phase of the [Ca2+]i increase.
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Affiliation(s)
- Kentaro Mizuta
- Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, 630 W. 168th St. P&S Box 46, New York, NY 10032, USA
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Godin N, Rousseau E. TRPC6 silencing in primary airway smooth muscle cells inhibits protein expression without affecting OAG-induced calcium entry. Mol Cell Biochem 2006; 296:193-201. [PMID: 16977347 DOI: 10.1007/s11010-006-9309-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 08/11/2006] [Indexed: 10/24/2022]
Abstract
TRPC proteins have been described as non-selective cation channels and are thought to be involved in the regulation of Ca(2+) movement in various cells, including airway smooth muscle (ASM) cells. In order to study the role of these channels in ASM cells, transfection of a small interfering RNA (siRNA) designed against the TRPC6 channel was performed in guinea pig primary ASM cells. This specific siRNA was complexed with the new X-TremeGene (X-TG) chemical transfection reagent, whose efficiency and low cytotoxicity were determined by the use of a non-silencing rhodamine-tagged siRNA. It was found that more than 95% of cells were transfected by an optimized protocol. Verification of TRPC6 transcript down-regulation was determined by RT-PCR while Western blot analysis attested to lower protein content in the microsomal fraction. Micro-spectrofluorimetry measurements of control and siRNA-treated cells revealed that lower TRPC6 expression did not affect OAG-induced intracellular Ca(2+) movement. Thus, TRPC6 channels cannot be defined as simple Ca(2+) transporters but more likely as protein complexes supporting monovalent cation conductance in ASM cells. These conductances would in turn facilitate membrane depolarization of high input resistance cells, Ca(2+) channel activation and tone increase. In conclusion, this study defines a valuable model of RNA interference study in primary cultures of ASM cells, eventually allowing for silencing of other target proteins for which no pharmacological modulators are currently available.
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Affiliation(s)
- Nicolas Godin
- Le Bilarium, Department of Physiology and Biophysics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th avenue north, J1H 5N4, Sherbrooke, QC, Canada
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