CHOLINESTERASES IN SYMPATHETIC FIBERS AND GANGLIA

Abstract

An investigation of the cholinesterases of the cat''s peripheral nerve fibers and ganglia by a microchemical method reveals a wide distribution of both true ChE and pseudo-ChE. In the superior cervical sympathetic ganglion both esterases are present in strong, practically equal conens. A study of the localization of the esterases within the ganglion shows that both are most active in the region where pregang-lionic endings and ganglion cells are most concentrated. In the cervical sympathetic trunk, most of the ACh hydrolysis is performed by true ChE. After preganglionic section the ganglion and degenerating preganglionic fibers lose true ChE at the same rate, suggesting that their common elements, preganglionic axons and endings, produce the enzyme. Ganglionic pseudo-ChE is lost at a much slower rate than true ChE, suggesting its production by some intrinsic element less affected by the operation, perhaps ganglion cells. Stripping the ganglion produced the expected chromatolysis. In addition, the resultant trauma or ischaemia produced even greater damage to the preganglionic endings, which disappeared entirely. Correlated with this was a total disappearance of true ChE and a marked reduction in pseudo-ChE content. The localization of true ChE in preganglionic axons and endings, as well as a study of the distribution of both esterases in cat and guinea pig ganglia and fibers, emphasizes the importance of true ChE in synaptic transmission and minimizes the physiologic significance of pseudo-ChE.