SPECIES DIFFERENCES IN THE DISTRIBUTION OF EXTRANEURONAL CHOLINESTERASES WITHIN THE VERTEBRATE CENTRAL NERVOUS SYSTEM

ALTHOUGH observations on the qualitative and quantitative distribution of ‘true’ or arxtykhohestemse arc extensive and generally consistent, there has been no systematic investigation of the phyletic distribution of ‘pseudo’ or butyrylcholinesterasc.+ The few recorded observations indicate that butyrylcholinesterase occurs not only in receptors such as the Pacinian corpuscle (HEBB and HILL, 1955), but also in the neuroglia cells and vascular endothelium in the central nervous system of the rat (KO1952) and cat (KOELLE, 1950). The vessel walls of the frog’s brain, however, exhibit no BuThChE, but only AChE activity (SHEN er ol., 1955). The present report is primarily concerned with the extraneuronal localization of cholinestem.5~~ within the central nervous system of several classes of vertebrates.