To quantitate calcium movements and membrane potential changes in stimulated neutrophils, we have measured net fluxes of Ca2+ and of the lipophilic cation tetraphenyl phosphonium by a very sensitive ion-selective electrode system. Activation of neutrophils by 3 X 10(-8) M phorbol 12-myristate, 13-acetate induces a release of approximately 20% of total cell calcium, with an initial lag period of...
