title: Airway Epithelial Cell Release of GABA is Regulated by Protein Kinase A.
abstract: γ-amino butyric acid (GABA) is not only the major inhibitory neurotransmitter in the central nervous system (CNS), but it also plays an important role in the lung, mediating airway smooth muscle relaxation and mucus production. As kinases such as protein kinase A (PKA) are known to regulate the release and reuptake of GABA in the CNS by GABA transporters, we hypothesized that β-agonists would affect GABA release from airway epithelial cells through activation of PKA.
  
  
  
  C57/BL6 mice received a pretreatment of a β-agonist or vehicle (PBS), followed by methacholine or PBS. Bronchoalveolar lavage (BAL) was collected and the amount of GABA was quantified using HPLC mass spectrometry. For in vitro studies, cultured BEAS-2B human airway epithelial cells were loaded with (3)H-GABA. (3)H-GABA released was measured during activation and inhibition of PKA and tyrosine kinase signaling pathways.
  
  
  
  β-agonist pretreatment prior to methacholine challenge attenuated in vivo GABA release in mouse BAL and (3)H-GABA release from depolarized BEAS-2B cells. GABA release was also decreased in BEAS-2B cells by increases in cAMP but not by Epac or tyrosine kinase activation.
  
  
  
  β-agonists decrease GABA release from airway epithelium through the activation of cAMP and PKA. This has important therapeutic implications as β-agonists and GABA are important mediators of both mucus production and airway smooth muscle tone.
authors.affiliation: Department of Anesthesiology, Columbia University, 630 W 168th St., P&S Box 46, New York, NY, 10032, USA. jd2757@cumc.columbia.edu.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Danielsson
authors.affiliation: Department of Pediatrics, Columbia University, New York, NY, 10032, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Zaidi
authors.affiliation: Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology, Columbia University, 630 W 168th St., P&S Box 46, New York, NY, 10032, USA.|Department of Pediatric Dentistry, Tsurumi University School of Dental Medicine, Yokohama, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Funayama
authors.affiliation: Department of Anesthesiology, Columbia University, 630 W 168th St., P&S Box 46, New York, NY, 10032, USA.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Yim
authors.affiliation: Department of Anesthesiology, Columbia University, 630 W 168th St., P&S Box 46, New York, NY, 10032, USA.
authors.forename: Dingbang
authors.initials: D
authors.lastname: Xu
authors.affiliation: Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA.
authors.forename: Tilla S
authors.initials: TS
authors.lastname: Worgall
authors.affiliation: Department of Anesthesiology, Columbia University, 630 W 168th St., P&S Box 46, New York, NY, 10032, USA.
authors.forename: George
authors.initials: G
authors.lastname: Gallos
authors.affiliation: Department of Anesthesiology, Columbia University, 630 W 168th St., P&S Box 46, New York, NY, 10032, USA.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Emala
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020536:Enzyme Activators / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism*; D005968:Glutamate Decarboxylase / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D017828:Rifabutin / Q000031:analogs & derivatives / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013726:Terbutaline / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism*
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D020536:Enzyme Activators; D020662:Guanine Nucleotide Exchange Factors; D010982:Platelet-Derived Growth Factor; C116122:RAPGEF3 protein, human; D012333:RNA, Messenger; C075278:platelet-derived growth factor A; D016210:Methacholine Chloride; D005576:Colforsin; D017828:Rifabutin; D005680:gamma-Aminobutyric Acid; C020754:herbimycin; D011433:Propranolol; D000242:Cyclic AMP; D020794:Receptor Protein-Tyrosine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; C401141:glutamate decarboxylase 2; D013726:Terbutaline
keywords: BEAS-2B; Bronchoalveolar lavage; Protein kinase A; Tyrosine receptor kinase; ³H-GABA release; β-agonist