ABSTRACT
This chapter focuses on attempts to measure cholinergic markers (acetylcholine synthesis, muscarinic and nicotinic receptors) in brain by the Positron Emission Tomography (PET) technique with special reference to Alzheimer’s disease. Information about the cholinergic system in the human brain has mainly been obtained from neurochemical studies performed in autopsy but rarely also in biopsy brain tissue. The neurochemical analysis have mainly been restricted to measurement of enzyme activities (acetylcholinesterase, choline acetyltransferase) and cholinergic muscarinic and nicotinic receptor densities. The PET technique is therefore of interest as a putative diagnostic tool in neurodegenerative diseases such as Alzheimer’s disease. Neurochemical studies in postmortem brain tissue from Alzheimer patients have revealed a marked deficit of the cortical nicotinic receptors. By using PET it is now possible to visualize receptor binding in human brain in vivo. For the cholinergic system in brain receptor studies using PET might be one way to visualize tracers for cholinergic function in brain.
