Depolarizing action of neostigmine at an autonomic ganglion

The actions of neostigmine have been examined using electrical recording from normal and denervated superior cervical ganglia from rat and kitten. Neostigmine produced a rapid and reversible depolarization of the ganglion cells, both in vitro and in vivo. This depolarization could be antagonized by hexamethonium, and was not related to an anticholinesterase action. Eserine blocked transmission and only produced a small depolarization of slow onset and development. This depolarization was reversible, but could not be antagonized by hexamethonium.