Cytosolic calcium, oxygen consumption and the intracellular pH of stimulated neutrophils.

The cytoplasmic pH undergoes a biphasic change when neutrophils are activated. The role of Ca2+ in initiating these changes was investigated. No correlation was found between the increased cytosolic [Ca2+] and the stimulation of the Na+/H+ antiport. Similarly, the cytoplasmic acidification elicited by activation in Na+-free media was found to be unrelated to [Ca2+]. Reversal of Na+/H+ exchange was also ruled out as the source of the acidification. Data using a variety of soluble activators indicate that metabolic acid generation is largely responsible for the observed drop in cytoplasmic pH.