The regulatory role of external cations on human polymorphonuclear phagocyte chemiluminescence

The effect of the external cations Na+ and Ca2+ on polymorphonuclear chemiluminescence was investigated. Both Ca2+ in the range of 0.2-2 mM and Na+ in the range of 114-143 mM showed a dose dependent increase in polymorphonuclear chemiluminescence, irrespective of the concurrent increase in osmolality. The Na+/H+ antiport inhibitor Amiloride decreased the response significantly. These effects were observed using buffers commonly used for chemiluminescence studies and indicate the importance of defining the Ca2+ and Na+ composition of the buffers used in chemiluminescence assays.