Chapter 7 The current status of the cortical cholinergic system in Alzheimer's disease and Parkinson's disease

Abstract

Publisher Summary The existence of a correlation between the loss of choline acetyltransferase (ChAT) activity and the severity of the dementia in Alzheimer's disease, suggest the existence of an important functional relationship between reduced activity of the cholinergic system and cognitive impairment. This relationship has recently been reinforced by the finding of a marked decrease in cortical ChAT activity in cognitively impaired Parkinsonian patients, which correlated with the severity of dementia. Attention has also recently been focussed on neuropathological changes in the nucleus of Meynert (located in the basal forebrain) in Alzheimer's disease and Parkinson's disease because this nucleus appears to be the source of the cortical cholinergic afferents. In the past few years, major advances have been made in understanding the neuroanatomical relationships between the nucleus of Meynert and its cortical cholinergic projections in animals and in the neurochemical, pharmacological, and electrophysiological characteristics of cortical cholinergic receptors. The changes that occur in this system in Alzheimer and Parkinson's diseases are, therefore, considered in the light of these recent advances and their therapeutic implications are discussed in the chapter.