Neurochemical characterization of an antimony-choline analog in rat cortical synaptosomes

An analog of choline, in which nitrogen was replaced by antimony, was neurochemically characterized in rat cortical synaptosomes. It was found to be a substrate for several cholinergic enzymes, transported by a Na+-dependent, hemicholinium-3-sensitive process, acetylated, and subsequently released by depolarization in a calcium-dependent manner. Sb-choline also completed with choline for Na+-dependent uptake and for acetylation by [14C]acetyl-CoA in synaptosomes. These results suggest that Sb-choline and its acetylated product should be useful substrates for the x-ray microanalytical localization of cholinergic pools in intact nerve terminals.