Figure 3.

Acetylcholine release process and the cholinergic hypothesis of AD. The cholinergic hypothesis of AD is based on the putative role of cholinergic neurons in learning, memory, and cognition. Deletion of cholinergic neurons in AD is evident from the low levels of CAT, AChR, or choline in key brain regions associated with cognition. As a therapeutic proof of concept, augmenting Ach release, increasing AChR activity, or increasing the lifespan of ACh can overcome the cholinergic neuron deficiency in AD pathology. In the latter case, inhibition of AChE is the common therapeutic approach for increasing the activity of surviving cholinergic neurons. Abbreviation: ACh, acetylcholine; Ac-CoA, acetyl-CoA; AChE, acetylcholinesterase; AChR, acetylcholine receptor; Ch, Choline; CAT, choline acetyl transferase; CoA, coenzyme A; ChT, Choline transporter (carrier); Ves, vesicle.