Mechanism of potentiation by manganese ion of aggregation of porcine pancreatic elastase-treated human platelets.
The effect of manganese ion (Mn2+) on the aggregation of porcine pancreatic elastase-treated platelets (ETP) induced by fibrinogen (Fbg) was studied. Mn2+ enhanced the aggregation of ETP on addition of Fbg specifically and dose-dependently. This effect of Mn2+ was not associated with the formation of thromboxane A2, and was not affected by pretreatment of ETP with acetylsalicylic acid in the presence of Mn2+. Moreover, it was not dependent on extracellular adenosine diphosphate, as shown by removal of extracellular adenosine diphosphate by pretreatment of ETP with creatine phosphate/creatine phosphokinase. Studies on the binding of 125I-Fbg to ETP showed that Mn2+ increased the Kd value of binding but did not affect the number of Fbg binding sites. These results indicate that Mn2+ specifically and dose-dependently potentiated Fbg-induced aggregation of ETP and that this effect of Mn2+ may be due to an increase in the affinity of binding of Fbg to the glycoprotein IIb-IIIa complex on the membranes of ETP.
Azuma
H
H
First Department of Internal Medicine, School of Medicine, University of Tokushima, Japan.
Shigekiyo
T
T
Miura
S
S
Uno
Y
Y
Saito
S
S
D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D008345:Manganese / Q000494:pharmacology*; D010196:Pancreatic Elastase / Q000494:pharmacology*; D010725:Phosphocreatine / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D010980:Platelet Membrane Glycoproteins / Q000502:physiology; D011487:Protein Conformation
D010980:Platelet Membrane Glycoproteins; D010725:Phosphocreatine; D008345:Manganese; D005340:Fibrinogen; D010196:Pancreatic Elastase; D001241:Aspirin