We stably expressed the rat D(1A) dopamine receptor in mouse fibroblast LTK- cells and obtained specific ligand binding and functional activity characteristic of the D(1A) dopamine receptor coupled to stimulation of adenylyl cyclase. In the transfected cells, the selective D1 agonist fenoldopam caused a concentration-dependent inhibition of Na+/K+-ATPase activity, achieving maximum inhibition of ~30%. The latter was abolished by the selective D1 antagonist (+)-SCH 23390 and by the specific protein kinase A inhibitor protein kinase inhibitor-(6-22) amide. In the nontransfected cells, fenoldopam did not affect Na+/K+-ATPase activity. 8- Chlorophenylthio-cAMP inhibited Na+/K+-ATPase activity in both transfected and nontransfected cells; this effect was blocked by protein kinase inhibitor-(6-22). These results indicate that the inhibition of Na+/K+- ATPase activity induced by agonist occupancy of D(1A) receptors is mediated by protein kinase A.
|Original language||English (US)|
|Number of pages||5|
|State||Published - 1993|
All Science Journal Classification (ASJC) codes
- Molecular Medicine