Pentamidine is a specific, non-peptide, GPIIb/IIIa antagonist.
Pentamidine was previously shown to act on glycoprotein (GP) IIb/IIIa (Cox et al., Thromb Haemost 1992; 68: 731). In this paper we study the effect of pentamidine on other RGD-dependent receptors. In a cell adhesion assay, pentamidine was 500 times more potent than RGDS at inhibiting platelet adhesion to fibrinogen. While RGDS inhibited platelet adhesion to fibronectin, endothelial cell adhesion to vitronectin or fibronectin, 293 cell adhesion to vitronectin, IMR 32 cell adhesion to fibronectin and C32 cell adhesion to vitronectin; pentamidine failed to inhibit these interactions at doses as high as 1 mM. Resting platelets fixed in the presence of 1 mM RGDS had increased binding of fibrinogen, i.e., RGDS activated GPIIb/IIIa, while pentamidine at 100 microM had no effect. Similarly, RGDS induced the binding of an anti-LIBS monoclonal antibody, while pentamidine had no effect. Pentamidine partially, but significantly, inhibited lysosome and alpha-granule release induced by the thrombin agonist peptide, while RGDS had no effect. Neither pentamidine nor RGDS affected ADP-induced Ca2+ influx. Pentamidine had no effect on ADP-induced intracellular pH changes while RGDS prevented the pH from returning to normal. Thus, pentamidine is a non-peptide GPIIb/IIIa antagonist that is non-activating and is specific for GPIIb/IIIa.
Cox
D
D
New Drug Research Laboratories, Fujisawa Pharmaceutical Company, Osaka, Japan.
Aoki
T
T
Seki
J
J
Motoyama
Y
Y
Yoshida
K
K
D000595:Amino Acid Sequence; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D002460:Cell Line; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects; D000939:Epitopes / Q000187:drug effects; D005340:Fibrinogen / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D010419:Pentamidine / Q000494:pharmacology*; D010973:Platelet Adhesiveness / Q000187:drug effects; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors*
D000981:Antiprotozoal Agents; D000939:Epitopes; D009842:Oligopeptides; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D010419:Pentamidine; D005340:Fibrinogen; C046617:arginyl-glycyl-aspartyl-serine