Procaine as an acetylcholine agonist in snail neuron.

Low concentrations of procaine (10(-5) M) are capable of provoking changes in the membrane potential of snail neurons. This effect is produced by direct application to the membrane and is characterized by a short response time and rapid reversibility. The resulting potential change has the same properties as that which follows acetylcholine application, including the same change of membrane resistance, the same relationship with membrane potential, the same ionic dependence and, finally, the same pharmacological sensitivity. The identity between the acetylcholine and procaine responses holds both for cells depolarized and cells hyperpolarized by acetylcholine. This procaine sensitivity involves only about two-thirds of the cells and it is concluded that procaine activates the cholinergic receptor on these cells.