Early Histamine Release and Death Due to Endotoxin

Abstract

Summary

The intravenous injection of a lethal dose of E. coli endotoxin into anesthetized dogs produces a precipitous fall in arterial blood pressure, a sharp increase in plasma histamine and an abrupt decrease in circulating platelets. The increase in histamine, like the fall in arterial pressure, occurs within 30-60 sec following the administration of a lethal dose of endotoxin. In contrast, sublethal doses of endotoxin produce only modest decreases in arterial blood pressure, no significant elevation in plasma histamine levels, and a slight fall in circulating platelets. In this study an increase in plasma histamine was always associated with a lethal outcome. In no instance was there death with no prior elevation in histamine. Results indicate that an early and marked increase in histamine seems to follow the injection of a lethal dose of endotoxin, and it is highly probable that this early release of histamine is in some way involved in both the cardiovascular changes and the ultimate lethality of this form of shock in the dog. The possible involvement of bradykinin, serotonin, and the catecholamines is indicated.