Tetrachlorodecaoxygen, a wound healing agent, produces vascular relaxation through hemoglobulin-dependent inactivation of serotonin and norepinephrine

We investigated the vasoactive actions of the wound-healing agent tetrachlorodecaoxygen (TCDO). TCDO (20 μM) had no direct effect on tone in isolated calf pulmonary arteries precontracted with potassium with or without 1 μM reduced hemoglobin under O₂ or N₂ atmosphere. However, TCDO, in a reduced hemoglobin-dependent manner, attenuated contraction produced by serotonin, associated with spectral changes consistent with destruction of serotonin. The loss of tone induced by serotonin catalyzed by TCDO plus reduced hemoglobin was not altered in the presence of superoxide dismutase (SOD) plus catalase. TCDO plus reduced hemoglobin also produced rapid relaxation of isolated rabbit aorta precontracted with norepinephrine (NE), whereas with phenylephrine (PE)-induced bone, the observed relaxation was slow to develop. Neither did TCDO, with or without reduced hemoglobin, alter soluble guanylate cyclase activity in pulmonary artery. Thus, a highly reactive species produced by interaction of TCDO with reduced hemoglobin appears to attenuate the contractile actions of serotonin, NE, and PE, selectively potentially by destroying these vasoactive agents. The vasodilator actions of TCDO (plus reduced hemoglobin) may contribute to wound healing by increasing nutrient blood flow and O₂ delivery needed for repair processes and bactericidal activity.