Effect of potassium cyanate on carbon monoxide and hypoxic hypoxia-induced lethality

Pretreatment of mice with potassium cyanate for 15 days resulted in a significant increase in hemoglobin-oxygen affinity (decrease in P 50) and a significant protection against hypoxic hypoxia-induced lethality. However, cyanate pretreatment had no significant effect on carbon monoxide-induced lethality. Oxygen consumption in cyanate-treated mice was significantly lower than in controls in room air but not different in hypoxic environments. Whether the protective effect of cyanate on hypoxic hypoxia-induced lethality is due to the increase in hemoglobin-oxygen affinity or attributable to a non-hemoglobin-related action of cyanate remains unresolved. Regardless, the need exists to reevaluate the current concept that changes in hemoglobin affinity for oxygen correlate with susceptibility to hypoxemic states. In addition, data presented together with previous findings support the concept that carbon monoxide lethality is not solely attributable to a carboxyhemoglobin-induced hypoxemia.