Effect of [Ca²⁺]_i on the release of NO from PMN, with Ca²⁺ present, assessed with the HbO₂ method as detailed in Materials and Methods, activated with LTC₄, LTD₄, and LTB₄(all at 100 nmol/L) compared with PMN treated with the Ca²⁺ chelator BAPTA-AM (5 μmol/L) in nominally Ca²⁺-free HBSS or with unstimulated PMN in HBSS with Ca²⁺. * .01 < P < .05; ** P< .01; mean ± SEM; n = 4.