Dopamine depolarizes podocytes via a D1-like receptor.
BACKGROUND
Dopamine influences glomerular haemodynamics and dopamine receptors have been demonstrated in the glomerulus, but little is known about the cellular effects of dopamine in glomerular cells. The aim of this study was to investigate the influence of dopamine on the cellular functions of podocytes.


METHODS
The effect of dopamine on membrane voltage was investigated in differentiated mouse podocytes. The membrane voltage was measured using the patch clamp technique. Reverse transcribed-polymerase chain reaction (RT-PCR) studies were performed to investigate the expression of dopamine receptor mRNA in mouse glomeruli and podocytes.


RESULTS
The addition of dopamine (100 nM-1000 microM) caused a concentration-dependent depolarization of podocytes (EC50 is approximate to 10 microM). Like dopamine, the selective agonist of the D1-like receptor, SKF 82958, depolarized podocytes in a concentration-dependent manner. (EC50 is approximate to 50 microM). SKF 82958 stimulated a time-and concentration-dependent accumulation of cyclic adenosine 3',5'-monophosphate (cAMP) in podocytes (EC50 is approximate to microM). RT-PCR studies with primers derived from mouse sequences amplified mouse mRNA for the D1-like and the D2-like receptor in glomeruli, which were obtained by the sieve technique, whereas only mRNA for the D1-like receptor was detected in cultured mouse podocytes.


CONCLUSIONS
The data indicate that dopamine induces a cAMP-dependent depolarization via a D1-like receptor in podocytes.
Bek
M
M
Department of Medicine, University of Freiburg, Germany.
Fischer
K G
KG
Greiber
S
S
Hupfer
C
C
Mundel
P
P
Pavenstädt
H
H
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D000242:Cyclic AMP / Q000032:analysis; D004298:Dopamine / Q000494:pharmacology*; D007678:Kidney Glomerulus / Q000187:drug effects* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D017447:Receptors, Dopamine D1 / Q000235:genetics / Q000502:physiology*
D001552:Benzazepines; D002712:Chlorides; D012333:RNA, Messenger; D017447:Receptors, Dopamine D1; C071262:SK&F 82958; D000242:Cyclic AMP; D004298:Dopamine