Relationship between changes in the content of acetylcholine and the activities of acetylcholinesterase and choline acetyltransferase in the hippocampus of the rat after septal lesions.

Changes in acetylcholine (ACh) content and acetylcholinesterase (AChE) and choline acetyltransferase (ChAc) activity in the hippocampus were compared after various septal lesions. With the use of a multiple regression model it was shown that the time course of the ACh and enzymic level changes is concordant after total destruction of the septum, but not always after partial damage. Septal lesions produced an effect mainly on bound ACh. The results suggest that the activity of AChE and ChAc is not the rate-limiting factor of the ACh level in the hippocampus. The involvement of other hippocampal neurotransmitters acting through the high-affinity uptake of choline is supposed to play an important role in ACh content regulation.