Identification of D/sub 1/-like dopamine receptors on human blood platelets
Dopamine is able to inhibit the epinephrine-induced aggregation of human blood platelets, but the mechanism of action has not been elucidated. In this study the authors report that membranes from human blood platelets possess high affinity, saturable and stereoselective binding sites for the D/sub 1/ dopamine receptor antagonist (/sup 3/H)SCH 23390. (/sup 3/H)SCH 23390 appeared to label a single class of binding sites with a B/sub max/ of 18.6 +- 1.6 fmolmg protein and a K/sub D/ of 0.8 nM. The potencies of different dopaminergic antagonists and agonists in displacing (/sup 3/H)SCH 23390 from blood platelet membranes were similar to those obtained for striatal membranes. Unlike the classically defined D/sub 1/ receptors, e.g. those in striatum, the D/sub 1/ receptor sites on platelets appeared no to be coupled to the adenylate cyclase system, hence the term D/sub 1/-like. The D/sub 1/ agonist SKF 38393 was more potent than dopamine in inhibiting platelet aggregation induced by epinephrine, and the effects of dopamine and SKF 38393 were prevented by SCH 23390. These results suggest that the inhibitory action of dopamine on the epinephrine-induced platelet aggregation is mediated through these D/sub 1/-like receptors
- Research Organization:
- Vrije Universiteit Brussel (Belgium)
- OSTI ID:
- 5298834
- Journal Information:
- Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 42:18; ISSN LIFSA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD COAGULATION
BLOOD PLATELETS
BODY FLUIDS
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CELL MEMBRANES
DOPAMINE
DRUGS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MAN
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NEUROREGULATORS
ORGANIC COMPOUNDS
PHENOLS
POLYPHENOLS
PRIMATES
PROTEINS
RECEPTORS
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES