Several central depressant and other drugs have been examined for their effects upon acetylcholine release from the stimulated, perfused cat superior cervical ganglion and rat isolated phrenic nerve-diaphragm preparations. The acetylcholine released was assayed biologically. Amylobarbitone sodium, chloral hydrate, trichloroethanol, methylpentynol, methylpentynol carbamate, paraldehyde, procaine hydrochloride and troxidone reduced the presynaptic release of acetylcholine from the ganglion. They also exhibited a postsynaptic blocking action, this component of depressant activity being particularly prominent with paraldehyde and troxidone. Closely analogous findings were obtained at the neuromuscular junction with methylpentynol and its carbamate, paraldehyde, procaine hydrochloride, trichloroethanol and troxidone. At both sites the drug-induced depression, both of transmission and of acetylcholine output, was reversible. Whereas hexamethonium regularly blocked ganglionic transmission with no effect upon acetylcholine release, tetraethylammonium not only completely blocked ganglionic transmission but concomitantly augmented acetylcholine output. These results are discussed in relation to the electrophysiological and metabolic events associated with neuro-effector transmission.

Acetylcholine↗

PubMed1963

THE EFFECTS OF CHOLINE AND OTHER FACTORS ON THE RELEASE OF ACETYLCHOLINE FROM THE STIMULATED PERFUSED SUPERIOR CERVICAL GANGLION OF THE CAT.

When the superior cervical ganglion of the cat was perfused with Locke solution, the amount of acetylcholine released into the perfusate decreased during successive periods of repetitive stimulation of the preganglionic nerve. Addition of choline to the perfusion fluid prevented this decrease. Choline also significantly increased (P<0.01) the initial output of acetylcholine. In contrast, variation of the physostigmine concentration or of the pCO(2) and pH of the perfusion fluid had no statistically significant effect (P>0.05) upon the initial release of acetylcholine.

Acetylcholine↗