Oxygen Uptake of Rainbow Trout Oncorhynchus Mykiss Phagocytes following Stimulation of the Respiratory Burst

The in vitro oxygen uptake of rainbow trout phagocyte-enriched head kidney leucocyte and head kidney macrophage suspensions was monitored. Stimulation of these cells with zymosan or phorbol myristate acetate induced a twoto 10-fold increase in oxygen uptake, the so-called respiratory burst. This respiratory burst activity was markedly enhanced in the presence of the calcium ionophore A23187 and inhibited in the presence of the NADPH oxidase inhibitor diphenyl iodonium or when glucose was absent from the buffer. The presence of sodium azide also inhibited the response of phagocyte-enriched suspensions by approximately 36 %, but only by 16 % for macrophage suspensions. The possible pathways responsible for the respiratory burst in fish phagocytes and its biological significance are discussed.