L-glutamic acid, a neurotrophic factor for maintenance of acetylcholinesterase and butyrylcholinesterase in the preganglionically denervated superior cervical ganglion of the cat.

In continuation of previous studies, the intraarterial fusion of L-glutamic acid for 24 hr was found to oppose the decrease in acetylcholinesterase and butyrylcholinesterase in the superior cervical ganglion of the cat that otherwise occurs 48 hr after preganglionic denervation. The combination of glutamic acid and gamma-aminobutyric acid, in concentrations that were inactive individually, likewise produced the same neurotrophic effect. Inactive in this respect were glycine plus L-glutamine, pyroglutamic acid, gamma-aminobutyric acid, and L-aspartic acid. The possible mechanisms and implications of these findings are discussed.