Oxidative burst by acellular haemoglobin and neurotransmitters.

Acellular haemoglobin (Hb) has intrinsic toxicity to the tissues since harmful reactive oxygen species are readily produced during auto-oxidation of Hb. On the other hand, Hb is known to have peroxidase-like activity monovalently oxidizing various peroxidase substrates. Thus, monovalently oxidized organic free radical species may be produced. This may relay the radical reactions leading to the production of reactive oxygen species such as superoxide. Such substrates possibly generating superoxide, include aromatic monoamines such as neurotransmitters and their precursors rich in neural a tissues. Based on our knowledge on the reactivity of haemoproteins against phenolics and aromatic monoamines, we proposed a hindered danger in use of Hb as a reperfusion agent. Clinical use of recently developing Hb-based blood substitutes must be reconsidered.