title: Pharmacological evidence for the stimulation of NADPH oxidase by P2X(7) receptors in mouse submandibular glands.
abstract: ATP in the 100 muM-1 mM concentration range provoked a calcium-independent increase of the oxidation of dichlorodihydrofluorescein (DCFH) to dichlorofluorescein (DCF) by mouse submandibular cells. 3'-O-(4-benzoyl)benzoyl adenosine 5'-triphosphate (BzATP), a P2X(7) agonist, but not a muscarinic or an adrenergic agonist, reproduced the effect of ATP. The inhibition of phospholipase C by U73122 or the potentiation of P2X(4) receptor activation with ivermectin did not modify the response to ATP. ATP did not increase the oxidation of DCFH in cells isolated from submandibular glands of P2X(7) knockout mice or in cells pretreated with a P2X(7) antagonist. The inhibition of protein kinase C or of mitogen-activated protein kinase (MAP kinase) or of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase blocked the oxidation of DCFH without affecting the increase of the intracellular concentration of calcium or the uptake of ethidium bromide in response to extracellular ATP. From these results it is concluded that the activation of the P2X(7) receptors from submandibular glands triggers an intracellular signalling cascade involving protein kinase C and MAP kinase leading to the stimulation of NADPH oxidase and the subsequent generation of reactive oxygen species.
authors.affiliation: Laboratoire de Biochimie et de Biologie Cellulaire, Institut de Pharmacie C.P. 205/3, Université libre de Bruxelles, Campus de la Plaine, Boulevard du Triomphe, 1050, Brussels, Belgium.
authors.forename: Michèle
authors.initials: M
authors.lastname: Seil
authors.forename: Unai
authors.initials: U
authors.lastname: Fontanils
authors.forename: Irantzu Gorrono
authors.initials: IG
authors.lastname: Etxebarria
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Pochet
authors.forename: Mikel
authors.initials: M
authors.lastname: Garcia-Marcos
authors.forename: Aida
authors.initials: A
authors.lastname: Marino
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Dehaye