title: Activation of phospholipase D-2 by P2X(7) agonists in rat submandibular gland acini.
abstract: Exogenous ATP stimulated phospholipase D (PLD), but not sphingomyelinase in rat submandibular gland (SMG) acini. PLD activation was dependent upon extracellular Ca(2+) and did not involve intracellular Ca(2+) mobilization or phosphoinositide-specific phospholipase C activation. ATP-stimulated PLD was attenuated by inhibition or downregulation of protein kinase C (PKC). PLD activation was fully blocked by the cytosolic phospholipase A(2) (PLA(2)) inhibitor ONO-RS-082 and partially attenuated by the selective Ca(2+)-dependent cytosolic PLA(2) inhibitor, arachidonyl trifluoromethylketone (AACOCF(3)), or by bromoenol lactone, an inhibitor of Ca(2+)-independent cytosolic PLA(2). Magnesium, which decreases the concentration of ATP(4-), and nickel, which blocks nonspecific cation channels coupled to purinergic receptors, inhibited PLD activation by ATP. Using reverse transcription-polymerase chain reaction and Northern blotting techniques, we demonstrated that the PLD isoform stimulated by ATP was PLD-2. Among various ATP analogs, only the P2Z/P2X(7) purinergic receptor agonist benzoyl-benzoyl ATP stimulated PLD-2. The response to ATP was inhibited by the nonselective P2X purinergic antagonist suramin and by oxidized ATP, a potent P2Z/P2X(7) receptor antagonist. It is concluded that in rat SMG acinar cells, PLD-2 is upregulated by exogenous ATP through a mechanism involving Ca(2+) influx, cytosolic PLA(2), and PKC. Also, the data suggest an involvement of P2X(7) receptors in PLD-2 stimulation by ATP.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain.
authors.forename: Encarnación
authors.initials: E
authors.lastname: Pérez-Andrés
authors.forename: María
authors.initials: M
authors.lastname: Fernández-Rodriguez
authors.forename: Mónica
authors.initials: M
authors.lastname: González
authors.forename: Ana
authors.initials: A
authors.lastname: Zubiaga
authors.forename: Ainara
authors.initials: A
authors.lastname: Vallejo
authors.forename: Itxaso
authors.initials: I
authors.lastname: García
authors.forename: Carlos
authors.initials: C
authors.lastname: Matute
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Pochet
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Dehaye
authors.forename: Miguel
authors.initials: M
authors.lastname: Trueba
authors.forename: Aida
authors.initials: A
authors.lastname: Marino
authors.forename: Antonio
authors.initials: A
authors.lastname: Gómez-Muñoz
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D004789:Enzyme Activation; D008297:Male; D051379:Mice; D010739:Phospholipase D / Q000378:metabolism*; D058910:Purinergic P2 Receptor Agonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D058486:Receptors, Purinergic P2X7; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013363:Submandibular Gland / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology
chemical_list: D017931:DNA Primers; C546469:P2rx7 protein, mouse; C546470:P2rx7 protein, rat; D058910:Purinergic P2 Receptor Agonists; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; C105606:phospholipase D2; D010739:Phospholipase D