title: Role of G proteins in shear stress-mediated nitric oxide production by endothelial cells.
abstract: Exposure of cultured endothelial cells to shear stress resulting from well-defined fluid flow stimulates the production of nitric oxide (NO). We have established that an initial burst in production is followed by sustained steady-state NO production. The signal transduction events leading to this stimulation are not well understood. In the present study, we examined the role of regulatory guanine nucleotide binding proteins (G proteins) in shear stress-mediated NO production. In endothelial cells not exposed to shear stress, AIF4-, a general activator of G proteins, markedly elevated the production of guanosine 3',5'-cyclic monophosphate (cGMP). Pretreatment with NO synthase inhibitor N omega-nitro-L-arginine completely blocked this stimulation. Incubation with guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), a general G protein inhibitor, blocked the flow-mediated burst in cGMP production in a dose-dependent manner. Likewise, GDP beta S inhibited NOx (NO2 + NO3) production for the 1st h. However, inhibition was not detectable between 1 and 3 h. Pertussis toxin (PTx) had no effect on the shear response at any time point. The burst in NO production caused by a change in shear stress appears to be dependent on a PTx-refractory G protein. Sustained shear-mediated production is independent of G protein activation.
authors.affiliation: Department of Chemical Engineering, Pennsylvania State University, University Park 16802.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kuchan
authors.forename: H
authors.initials: H
authors.lastname: Jo
authors.forename: J A
authors.initials: JA
authors.lastname: Frangos
mesh_terms: D017607:Aluminum Compounds / Q000494:pharmacology; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005459:Fluorides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D009569:Nitric Oxide / Q000096:biosynthesis*; D009994:Osmolar Concentration; D037342:Pertussis Toxin; D013314:Stress, Mechanical; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D017607:Aluminum Compounds; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D006153:Guanosine Diphosphate; C050992:tetrafluoroaluminate; D009569:Nitric Oxide; C023427:guanosine 5'-O-(2-thiodiphosphate); D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D006152:Cyclic GMP; D005459:Fluorides