Role of cAMP-PKA-PLC signaling cascade on dopamine-induced PKC-mediated inhibition of renal Na(+)-K(+)-ATPase activity.
We studied the molecular events set into motion by stimulation of D(1)-like receptors downstream of Na(+)-K(+)-ATPase, while measuring apical-to-basal ouabain-sensitive, amphotericin B-induced increases in short-circuit current in opossum kidney (OK) cells. The D(1)-like receptor agonist SKF-38393 decreased Na(+)-K(+)-ATPase activity (IC(50), 130 nM). This effect was prevented by the D(1)-like receptor antagonist SKF-83566, overnight cholera toxin treatment, the protein kinase A (PKA) antagonist H-89, or the PKC antagonist chelerythrine, but not the mitogen-activated PK inhibitor PD-098059 or phosphatidylinositol 3-kinase inhibitors wortmannin and LY-294002. Dibutyryl cAMP (DBcAMP) and phorbol 12,13-dibutyrate (PDBu) both effectively reduced Na(+)-K(+)-ATPase activity. PKA downregulation abolished the inhibitory effects of SKF-38393 and DBcAMP but not those of PDBu. PKC downregulation abolished inhibition by PDBu, SKF-38393, and DBcAMP. The phospholipase C (PLC) inhibitor U-73122 prevented inhibition by SKF-38393 and DBcAMP. However, DBcAMP increased PLC activity. Although OK cells express both G(s)alpha and G(q/11)alpha proteins, D(1)-like receptors are coupled to G(s)alpha proteins only, as evidenced by studies in cells treated overnight with specific antibodies raised against G(s)alpha and G(q/11)alpha proteins. We conclude that PLC and Na(+)-K(+)-ATPase are effector proteins for PKA and PKC, respectively, after stimulation of D(1)-like receptors coupled to G(s)alpha proteins, in a sequence of events that begins with adenylyl cyclase-PKA system activation followed by PLC-PKC system activation.
Gomes
Pedro
P
Institute of Pharmacology and Therapeutics, Faculty of Medicine, 4200 Porto, Portugal.
Soares-da-Silva
P
P
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D015194:Diffusion Chambers, Culture; D004298:Dopamine / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D020536:Enzyme Activators / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018942:Macrolides; D008564:Membrane Potentials / Q000187:drug effects; D009893:Opossums; D011493:Protein Kinase C / Q000378:metabolism*; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D018491:Dopamine Agonists; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D018942:Macrolides; D017447:Receptors, Dopamine D1; D003994:Bucladesine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D010738:Type C Phospholipases; D019205:GTP-Binding Protein alpha Subunits, Gs; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium; D004298:Dopamine