title: D3 dopamine receptor activates phospholipase D through a pertussis toxin-insensitive pathway.
abstract: Within the dopamine receptor family, the D(3) dopamine receptor's function remains inadequately described. The D(3) receptor has been shown to couple to inhibition of adenylyl cyclase, stimulation of mitogenesis, and regulation of K(+) and Ca(2+) currents, all in a pertussis toxin (PTX)-sensitive manner. Here we report D(3) receptor activation of the phospholipase D (PLD) enzyme in HEK 293 cells heterologously expressing the human D(3) receptor. Activation by agonist is dose dependent and displays the pharmacology expected of the D(3) receptor. The D(3) receptor specific antagonists AJ-76 and U99194A ablated the increase in activity by the preferring D(3) agonist (+) 7-OH DPAT. In addition, the D(3) receptor-mediated activation of PLD is not mediated by G-proteins of the G(i)/G(o) family, as pretreatment with PTX had no effect. PLD activation is a novel finding for the D(3) receptor, and is the first example of an effector system where D(3) signals without G(i)/G(o) protein intermediates.
authors.affiliation: Department of Molecular Sciences, University of Tennessee Health Science Center, Suite G01, 858 Madison Avenue, Memphis, TN 38163, USA.
authors.forename: P Benjamin
authors.initials: PB
authors.lastname: Everett
authors.forename: Susan E
authors.initials: SE
authors.lastname: Senogles
mesh_terms: D002478:Cells, Cultured; D018491:Dopamine Agonists / Q000494:pharmacology; D004789:Enzyme Activation / Q000502:physiology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology; D037342:Pertussis Toxin / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
chemical_list: C493593:DRD3 protein, human; D018491:Dopamine Agonists; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes; D037342:Pertussis Toxin; D010739:Phospholipase D; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; C031349:7-hydroxy-2-N,N-dipropylaminotetralin