title: Expression and coupling of neurokinin receptor subtypes to inositol phosphate and calcium signaling pathways in human airway smooth muscle cells.
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.
authors.affiliation: Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, 630 W. 168th St. P&S Box 46, New York, NY 10032, USA.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Mizuta
authors.forename: George
authors.initials: G
authors.lastname: Gallos
authors.forename: Defen
authors.initials: D
authors.lastname: Zhu
authors.forename: Fumiko
authors.initials: F
authors.lastname: Mizuta
authors.forename: Farida
authors.initials: F
authors.lastname: Goubaeva
authors.forename: Dingbang
authors.initials: D
authors.lastname: Xu
authors.forename: Reynold A
authors.initials: RA
authors.lastname: Panettieri
authors.forename: Jay
authors.initials: J
authors.lastname: Yang
authors.forename: Charles W
authors.initials: CW
authors.lastname: Emala
mesh_terms: D001896:Boron Compounds / Q000494:pharmacology; D020013:Calcium Signaling / Q000502:physiology*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015288:Neurokinin A / Q000031:analogs & derivatives / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D018040:Receptors, Neurokinin-1 / Q000819:agonists / Q000096:biosynthesis* / Q000502:physiology; D018041:Receptors, Neurokinin-2 / Q000819:agonists / Q000096:biosynthesis* / Q000502:physiology; D018042:Receptors, Neurokinin-3 / Q000819:agonists / Q000096:biosynthesis* / Q000502:physiology; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D001896:Boron Compounds; D007093:Imidazoles; D010446:Peptide Fragments; D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; D018042:Receptors, Neurokinin-3; C054724:senktide; C062618:substance P, Sar(9)-Met(O2)(11)-; C064218:neurokinin A (4-10), beta-Ala(8)-; D013373:Substance P; D015544:Inositol 1,4,5-Trisphosphate; D015288:Neurokinin A; C109986:2-aminoethoxydiphenyl borate; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole