DOPAMINE D-3 RECEPTORS IN RAT JUXTAGLOMERULAR CELLS

D-2-like receptors in the kidney have been suggested to be important i n the regulation of renin release but the D-2-like subtype(s) expresse d in juxtaglomerular (JG) cells is not known. Therefore, we determined which of the D-2-like family of dopamine receptors is located in prim ary cultures of rat juxtaglomerular (JG) cells. Reverse transcriptase- polymerase chain reaction (RT-PCR) identified D-3 and D-4 but not D-2L ong mRNA in JG cells (n=3). D-3 receptor function was demonstrated by a concentration-dependent inhibition of forskolin-stimulated cAMP prod uction by LY-171555 (a nea-selective D-2-like receptor agonist) and PD -128593 (a partially selective D-3 agonist) (n=3-7/group). The stimula tory action of LY-171555 and PD-128593 we blocked by the non-selective D-2-like antagonist YM-09151. We conclude that D-3 and D-4 dopamine r eceptor subtypes ape expressed in JG cells; the receptor subtype linke d to the inhibition of cAMP in JG cells remains to be established.