17-beta-oestradiol-induced vasorelaxation in vitro is mediated by eNOS through hsp90 and akt/pkb dependent mechanism.
1. The L-arginine-NO pathway has been implicated in the vasorelaxant effect of 17-beta-oestradiol. Here we have addressed the involvement of two distinct activation steps of endothelial nitric oxide synthase (eNOS) in the 17-beta-oestradiol-induced vasorelaxant effect on rat aortic rings. 2. Rat aortic rings contracted with phenylephrine (PE) 1 microM relaxed in a concentration related fashion to 17-beta-oestradiol water soluble cyclodextrin-encapsulated (E2) only when endothelium was present. The pure anti-oestrogen of E2 receptor ICI 182,780 (20 microM) significantly inhibited E2-induced vasorelaxation. 3. Geldanamycin (10 microM), a specific inhibitor of heat shock protein 90 (hsp90) and N(omega)-nitro-L-arginine-methyl ester (L-NAME, 100 microM), a nitric oxide synthase inhibitor, significantly inhibited E2-induced vasorelaxation. 4. Incubation of rat aortic rings up to 6 h with LY 294002 (25 microM), a specific inhibitor of PI(3)K akt/pkb pathway reduced E2-induced vasorelaxation. 5. Incubation of rat isolated aorta with E2, induced prostacyclin (PGI(2)) release. PGI(2) levels, measured as 6-keto PGF(1alpha), were abolished by ibuprofen (10 microM), both L-NAME and GA did not influence basal or E2-stimulated PGI(2) confirming the specificity of these two compounds on eNOS pathway. 6. In conclusion, we demonstrate that E2 interaction with its receptor is followed by a vasorelaxant effect in rat aortic rings mediated by eNOS activation through both hsp90 and akt/pkb dependent mechanisms.
Bucci
Mariarosaria
M
Department of Pharmaceutical Science, Faculty of Pharmacy, University of Salerno, Fisciano (SA) Italy.
Roviezzo
Fiorentina
F
Cicala
Carla
C
Pinto
Aldo
A
Cirino
Giuseppe
G
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D002867:Chromones / Q000494:pharmacology; D004347:Drug Interactions; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000378:metabolism; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D000077267:Fulvestrant; D018841:HSP90 Heat-Shock Proteins / Q000502:physiology*; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors; D014664:Vasodilation / Q000187:drug effects*
D002867:Chromones; D004791:Enzyme Inhibitors; D004965:Estrogen Antagonists; D018841:HSP90 Heat-Shock Proteins; D009025:Morpholines; D011518:Proto-Oncogene Proteins; D011960:Receptors, Estrogen; D000077267:Fulvestrant; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D004958:Estradiol; D011464:Epoprostenol; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt