Regulatory changes in presynaptic cholinergic function assessed in rapid autopsy material from patients with Alzheimer disease: Implications for etiology and therapy

Brain regions from patients with or without Alzheimer disease (AD) were obtained within 2 hr of death and examined for indices of presynaptic cholinergic function. Consistent with loss of cholinergic projections, cerebral cortical areas involved in AD exhibited decreased choline acetyltransferase (acetyl-CoA:choline 0-acetyltransferase, EC 2.3.1.6) activity. However, remaining nerve terminals in these regions displayed marked up-regulation of synaptosomal high affinity [³H]choline uptake, a result indicative of relative cholinergic hyperactivity. As choline uptake is also rate-limiting in acetylcholine biosynthesis, these findings have implications for both therapy and identification of causes contributing to neuronal death in AD.