Anthrax toxin: primary site of action.

The site of action of Bacillus anthracis toxin in the rhesus monkey was the central nervous system.(CNS). Injection of toxin directly into the cerebrospinal fluid produced death in 6 Lo 10 minutes, in contrast with the 30 hours required to kill when 10 times this dose was given intravenously. During this short period of toxemia, the monitored physiological systems changed drastically, indicative of a tremendous increase in CNS discharges, resulting in terminal anoxia. Inactivation of the toxin with antiserum or heat prevented the lethal effect; the animals survived. If respiration could be maintained, the animals also survived toxin challenge. Maintenance of respiration was achieved by artificial ventilation and reestablished by the intravenous injection of a beta adrenergic stimulant, isoprvtz: nol hydrochloride (Isuprel).