Effect of Locally Applied Hemicholinium on the Acetylcholine Content of the Caudate Nucleus

Abstract

ALPHA, alpha-dimethylethanolamino-4, 4′-biacetophenone (hemicholinium-3 or HC-3) is known to inhibit acetylcholine synthesis both in peripheral structures¹ and in the brain². Since it causes death from respiratory failure when given parenterally, detailed investigations of its actions have so far been confined to isolated, perfused structures such as the superior cervical ganglion, while its effects on brain centres, like the caudate nucleus, which have the ability to synthesize acetylcholine at a high rate, have not been analysed. In this report we describe experiments in which we have observed the effects of HC-3, injected directly into the caudate nucleus of the rat, on the acetylcholine content of the nucleus, and on its ability to convert radioactive choline to acetylcholine.