1. Na+/H+ antiport activity was measured in peripheral blood polymorphonuclear and mononuclear cells of 12 healthy subjects by using an intracellular pH clamp technique to determine the external Na+-dependent H+ efflux rate in cells loaded with a pH-sensitive fluorescent dye, bis(carboxyethyl)carboxyfluorescein. The change in external Na+ concentrations for all pH measurements was similar in both cell types.

2. A significant difference between the two types of cells was found, the polymorphonuclear leucocytes having a higher Na+/H+ antiport activity than the lymphocytes. Cellular intrinsic buffering capacity measured in the absence of HCO3 was also higher in the polymorphonuclear cells than in the lymphocytes.

3. These differences may be associated with a difference in the role of the Na+/H+ exchanger in these two types of cells, although in vivo the presence of HCO3/Cl exchangers may also contribute to intracellular pH homoeostasis.

This content is only available as a PDF.
You do not currently have access to this content.