Na+/H+ antiport and buffering capacity in human polymorphonuclear and mononuclear leucocytes.
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.
Frighi
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Sheikh Rashid Diabetes Unit, Radcliffe Infirmary, Oxford, U.K.
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Lewis
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A
Dhar
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D000328:Adult; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D002021:Buffers; D002352:Carrier Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007962:Leukocytes / Q000378:metabolism*; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D008536:Meglumine / Q000494:pharmacology; D009504:Neutrophils / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers
D000889:Anti-Arrhythmia Agents; D002021:Buffers; D002352:Carrier Proteins; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride; D008536:Meglumine; D000584:Amiloride; D006859:Hydrogen; C039614:ethylisopropylamiloride