Thromb Haemost 1987; 58(04): 971-977
DOI: 10.1055/s-0038-1646039
Original Article
Schattauer GmbH Stuttgart

Characterization of Na+/H+ Exchange in Platelets

Avinoam Livne
The Division of Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
,
Sergio Grinstein
The Division of Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
,
Aser Rothstein
The Division of Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
› Institutsangaben
Weitere Informationen

Publikationsverlauf

Received 10. Dezember 1986

Accepted after revision 03. Juli 1987

Publikationsdatum:
29. Juni 2018 (online)

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Summary

Acidification of the cytoplasm of human blood platelets leads to activation of Na+/H+ exchange. As a result, alkalinization occurs that is detectable by an intracellular fluorescent pH indicator. The activity of the exchanger can also be measured by the swelling of platelets suspended in Na-propionate medium using a Coulter Counter: the rapid entry of propionic acid leads to acidification and activation of Na+/H+ exchange with the parallel entry of Na+ and propionic acid leading to osmotic swelling. The Na+/H+ exchanger is sensitive to amiloride and to derivatives that are reported to be more specific inhibitors; it is specific for Na+ and Li+ with no measurable transfer of K+, Rb+ or Cs+; its Km for Na+ is 75 to 90 mM; it displays competitive behavior between Na+ and amiloride; its activity is decreased in cells loaded with Na+ by prolonged ouabain treatment; and it has a high temperature coefficient. These properties are in general similar to those of the exchanger in other cells. It is suggested that the Na+/H+ exchanger plays a role in platelet pH regulation.