A chemiluminescent probe with a <i>Cypridina</i> luciferin analog, 2‐methyl‐6‐phenyl‐3,7‐dihydroimidazo[1,2‐a]pyrazin‐3‐one, specific and sensitive for O₂⁻ production in phagocytizing macrophages

Abstract

When a Cypridina luciferin analog (the title compound) was added to a macrophage suspension in Hank's balanced salt solution (control), the system emitted a weak, but detectable light, which was not altered in the presence of superoxide dismutase. The same system, however, emitted a much stronger light, just after the addition of a trigger, opsonized zymosan. The luminescence was suppressed to the control level in the presence of superoxide dismutase, while it was only slightly influenced, if at all, by NaN3, a scavenger of singlet oxygen and an inhibitor of myeloperoxidase. Some other results obtained also indicate the participation of O2- in the luciferin analog-dependent luminescence in macrophages during phagocytosis.