The Role of Glial Cells in Neuronal Acetylcholine Synthesis

Abstract

Earlier reports have suggested that the choline (Ch) supply for acetylcholine (ACh) synthesis may originate from the blood (1), or be released (5), or synthesized de novo by different enzymes in the brain (9). There are no data, however, on the role of glial cells in neuronal ACh synthesis. Some years ago, Tuček (12) put forward the idea that Ch may be produced in the glial cells, from where it passes into the extracellular fluid, and is then taken up by the high-affinity (16) carrier system into the cholinergic axon terminals. On the basis of biochemical investigations, Ansell and Spanner (2) have suggested that glycerophosphocholine diesterase (GPCD: EC 3.1.4.2) may be important in the release of Ch from the glial cells. It has also been noted that central neurons “fare better” in cultures when in contact with non-neuronal cells (13), and especially glial cells (11). Since neither the fate of the Ch released from the glial cells nor the role of the contact between glial cells and neurons has yet been elucidated, our aim was to investigate these phenomena.