Abstract
An antiserum raised to nerve terminal sacs derived from the electric organ of Torpedo marmorata was used to lyse guinea pig brain synaptosomes in the presence of complement. From the release of the cytoplasmic enzymes choline acetyltransferase [EC 2.1.1.6], lactate dehydrogenase [EC 1.2.1.22], tyrosine hydroxylase [EC 1.14.16.2] and glutamate decarboxylase [EC 4.1.1.15], it appears that the antiserum binds specifically to cholinergic terminals. The amount of lactate dehydrogenase released was used to estimate the proportion of cholinergic nerve terminals in different synaptosome preparations.