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Prostaglandin D 2 interacts at thromboxane receptor‐sites on guinea‐pig platelets
Author(s) -
HamidBloomfield S.,
Whittle B.J.R.
Publication year - 1986
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1986.tb16268.x
Subject(s) - thromboxane receptor , thromboxane , guinea pig , chemistry , thromboxane a2 , platelet , receptor , antagonist , prostaglandin , prostaglandin d2 , antagonism , prostanoid , medicine , receptor antagonist , endocrinology , pharmacology , biology , biochemistry
1 The anti‐aggregatory prostanoid, prostaglandin D 2 (PGD 2 ) does not completely inhibit ADP‐induced aggregation of guinea‐pig platelets and thus produces a bell‐shaped dose‐inhibition curve. The nature of this bell‐shaped curve has now been investigated in guinea‐pig platelet‐rich plasma. 2 Two selective thromboxane receptor antagonists, 13‐aza‐prostanoic acid (13‐AZA; 16–64.4 μ m ) and BM 13.177 (5.9–29.8 μ m ), converted PGD 2 to a full inhibitor of aggregation in a dose‐related manner. 3 The putative platelet PGD 2 receptor antagonist, N‐0164 (75 μ m ) also converted PGD 2 to a full inhibitor of platelet aggregation. In contrast to 13‐AZA and BM 13.177, higher concentrations of N‐0164 (380 and 760 μ m ) caused a dose‐related rightward shift of the PGD 2 dose‐inhibition curve. 4 The thromboxane receptor antagonism of N‐0164 was confirmed in studies in which the dose‐aggregation curve to U‐46619, a thromboxane mimetic, was competitively antagonized with a pA 2 value of 4.67 and a slope of 1.13, comparable to that of 13‐AZA. 5 The results show that N‐0164 acts as both a platelet PGD 2 and thromboxane‐receptor antagonist in both human and guinea‐pig platelet‐rich plasma. 6 The results further indicate that PGD 2 can interact at thromboxane receptors in guinea‐pig platelets.