Effect of Pseudomonas pseudomallei Endotoxin on Response to Cholinergic Stimuli in the Rabbit. ∗

Summary

Pseudomonas pseudomallei endotoxin induced in rabbits, after a latent period, an increased response of pulmonary cholinergic vasoconstrictor mechanisms to intravenous injection of acetylcholine. This effect was not found either in rats or guinea pigs. An increased response of cholinergic vasodilator mechanisms in the major circulation to AC was not clearly demonstrated. Cardiac rate and rhythm, central venous pressure, portal pressure and resistance in the respiratory passages were not significantly affected by injection of AC either before or after administration of endotoxin. Endotoxin did not alter the response to stimulation of parasympathetic nerves in any of the cholinergic structures investigated. Only low doses of endotoxin and AC were required to produce the observed phenomenon. The possible role of endotoxin in sensitizing cholinergic mechanisms to AC in the pathogenesis of endotoxin shock in rabbits is discussed.