Nicotinic acetylcholine receptors and imaging.

In vivo imaging techniques like positron emission tomography (PET) and single photon emission computed tomography (SPECT) offer the possibility to monitor human central nicotinic acetylcholine receptors (nAChRs) in a variety of central nervous system disorders. In the past, the only available PET radiotracer for imaging nAChRs in the human brain, [11C]-(-)-nicotine, suffered from a spectrum of not suitable properties for in vivo imaging. Current efforts are focused on the development of new, highly specific and highly selective radioligands based on different structural classes (e.g. nicotine, epibatidine, 3-pyridyl ether analogues) for central nAChRs. The most promising compounds are halogenated 3-pyridyl ether compounds for imaging alpha 4 beta 2 nAChRs. But there is still a lack for radiotracers for other subtypes of nicotinic acetylcholine receptors being a promising area of interest.