Dopamine receptors mediating inhibition of the cyclic adenosine monophosphate generating system in the rat renal cortex.
1. In vitro addition of dopamine (DA) or of DA-1 receptor agonists increases 3'- 5'-cyclic adenosine monophosphate (cAMP) levels through the stimulation of DA-1 receptors. 2. Although receptor binding studies suggest the existence of DA-2 receptors in the renal cortex, the presence of DA receptors negatively coupled to cAMP generation (DA-2 effect) has not been so far characterized. 3. In this study we have shown that the addition of DA plus the selective DA-1 receptor antagonist SCH 23390 to membrane fractions of rat renal cortex decreased cAMP concentration below basal levels. 4. DA-2 receptor responses were also elicited with the DA-2 receptor agonists bromocriptine and quinpirole in the absence of SCH 23390. These inhibitory effects on cAMP generation were abolished by the DA-2 receptor antagonist 1-sulpiride. 5. The above findings are indicative of the existence in the rat renal cortex of DA-2 receptors showing an effect upon cAMP generation similar to that found in the brain and in several peripheral tissues.
Dipartimento di Scienze Cardiovascolari e Respiratorie, Università La Sapienza, Roma, Italy.
A
A
Ricci
W L
WL
Collier
I
I
Rossodivita
F
F
Amenta
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D001971:Bromocriptine / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D004298:Dopamine / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology; D004873:Ergolines / Q000494:pharmacology; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000378:metabolism*; D008297:Male; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*
D001552:Benzazepines; D015259:Dopamine Agents; D004873:Ergolines; D011954:Receptors, Dopamine; D019257:Quinpirole; D001971:Bromocriptine; D000242:Cyclic AMP; D004298:Dopamine