Effects of anoxia and hypercapnia on plasma histamine concentration blood plasma histamine concentration plasma histamine concentration

Abstract

Experiments are carried out in dogs and rabbits observing the variations of histamine concentration in the blood in conditions of anoxia and hypercapnia. Anoxia without hypercapnia always gives rise to an elevation of histamine concentration. Hypercapnia diminishes histaminaemia. When anoxia is accompanied by hypercapnia, the histamine concentration of the plasma either does not vary or else diminishes.

It is suggested, as a probable interpretation of these phenomena that histaminase activity is inhibited by anoxia; further that hipercapnia activates histaminase through diminution of pH. The activity of histidin-decarboxilase disminishe for the same reason. According to previous investigations by the same authors, they suppose that a increase of CO2 in the blood plasma is capable of producing a fixing of histamine in the plasmatic proteins.