title: GPER-1 agonist G1 induces vasorelaxation through activation of epidermal growth factor receptor-dependent signalling pathway.
abstract: OBJECTIVE
  The G protein-coupled oestrogen receptor-1 (GPER-1) agonist G1 induces endothelium-dependent relaxation. Activation of the epidermal growth factor (EGF) receptor leads to transduction of signals from the plasma membrane for the release of nitric oxide. We tested the hypothesis that G1 induces endothelium-dependent vasorelaxation through activation of the EGF receptor.
  
  
  METHODS
  Rat aortic rings were mounted in organ baths. After pretreatment with various inhibitors, aortic rings contracted with 11,9-epoxymethano-prostaglandin F2α or KCl were subjected to relaxation by G1.
  
  
  RESULTS
  G1 induced endothelium-dependent vasorelaxation, which was attenuated by pretreatment with either L -N(ω) -nitroarginine methyl ester (L -NAME), an inhibitor of nitric oxide synthase, or (3aS,4R,9bR)-4-(6-bromo-1,3-benzodioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline HB-EGF, heparin-binding EGF-like growth factor, a GPER-1 antagonist. Neither a general oestrogen receptor antagonist, ICI 182 780, nor a selective oestrogen receptor-α antagonist, methyl-piperidino-pyrazole dihydrochloride (MPP), had an effect on G1-induced vasorelaxation. However, pretreatment with EGF receptor blockers, AG1478 or DAPH, resulted in attenuated G1-induced vasorelaxation. In addition, pretreatment with Src inhibitor 4-amino-3-(4-chlorophenyl)-1-(t-butyl)-1H-pyrazolo[3,4-d]pyrimidine, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine or Akt inhibitor VIII also resulted in attenuated vascular relaxation induced by the cumulative addition of G1. However, neither phosphatidylinositol-3 kinase inhibitors LY294002 and wortmannin nor an extracellular signal-regulated kinase inhibitor 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto) butadiene monoethanolate had effect on vascular relaxation induced by the cumulative addition of G1.
  
  
  CONCLUSIONS
  G1 induces endothelium-dependent vasorelaxation through Src-mediated activation of the EGF receptor and the Akt pathway in rat aorta.
authors.affiliation: Department of Pharmacology, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Jang
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Seok
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Arterburn
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Olatunji
authors.forename: In Kyeom
authors.initials: IK
authors.lastname: Kim
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000819:agonists*; D015398:Signal Transduction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C520305:Gper1 protein, rat; D043562:Receptors, G-Protein-Coupled; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt
keywords: G protein-coupled oestrogen receptor-1; G1; Src and PI3K/Akt pathway; endothelium-dependent vasorelaxation; epidermal growth factor receptor