Blocking action of decamethonium at different sites in the autonomic nervous system of the cat.

Doses of decamethonium sufficient to paralyse skeletal and respiratory muscles in the cat for 20 to 30 min can reversibly block transmission at several sites in the autonomic nervous system. The sympathetic vasodilator outflow to skeletal muscle was blocked at the post-ganglionic nerve endings, probably by preventing the release of acetylcholine. The effects of vagal stimulation on heart-rate and intestinal contraction were blocked in most experiments, possibly by an action on pre-ganglionic as well as post-ganglionic nerve endings. However, decamethonium did not block all cholinergic nerve endings-for example, it did not diminish either the effects of stimulation of the chorda tympani on the submandibular salivary gland or those of pelvic nerve stimulation on the bladder.