The intracellular pH of the human platelet.

Abstract

The intra-cellular pH of the human platelet was measured in Krebs-Ringer bicarbonate buffer by use of 5,5-dimethyl-2,4-oxazolidine-dione-2-C14 (DM0). Extra-cellular pH was varied by changing CO2 tension or bicarbonate concentration. The platelet maintained a H ion gradient over a wide range of external pH. Cellular pH was much more sensitive to changes in external CO2 tension than to changes in bicarbonate concentration, although the concentration of external bicarbonate did influence H ion activity without the cell. Thrombin, p-chloromercuribenzoic acid Na salt (PCMB), and cyanide impaired the ability of the platelet to maintain a H ion gradient. Fluoride, iodoacetate, and a number of other agents did not. The changes in intra-cellular pH produced by variation in external pH were not accompanied by changes in the concentration of intra-cellular K.