[Inhibitory influence on the heart of antidromal stimulation of afferent fibers of the vagus nerve].

In partially or completely deparasympathized frogs, inhibition was not potentiated by the specific inhibitor of "true" cholinesterase acetylcholinesterase: the 1,5-bis(4-tri-methylammoniumphenylpeptan-3-on-diiodide). The localization of cardiac "true cholinesterase" being determined only in the region of the postsynaptic membrane of post-ganglionic neurons, this enzyme lacking on their extrasynaptic surface and in the myocardium, it was concluded that excitatory effect of antidromic afferent activation on the intracardiac neurons was due to action of acetylcholine (released from the nerve endings) on the extrasynaptic region of neurons' membrane. These regions acquire cholino-receptive features after preganglionic parasympathetic degeneration.