Neuronal nicotinic acetylcholine receptor agonists

Nicotinic acetylcholine receptors (nAChRs) consist of five protein subunits surrounding a central ion channel. Although a considerable diversity of subunit combinations are possible, it seems that some may predominate. The current literature provides evidence that nAChRs may represent a rational target for the treatment of several diseases, including Parkinson's disease, Alzheimer's disease, pain, tobacco dependency, schizophrenia, anxiety and depression. However, there are a number of remaining issues, particularly in minimising the potential side effects of nicotinic ligands, such as their action on the cardiovascular and gastrointestinal systems, drug dependence and sleep disturbance. The research for selective agents able to activate specific subtypes of nAChRs has been seen as a good opportunity to identify new potential drugs; this has led to a number of compounds belonging to different chemical classes. As far as nicotinic ligands are concerned, five classes with a high affinity for the alpha(4)beta(2)- and alpha(7)-nAChRs were recently described by Schmitt. This review discloses recent reports from the patent literature of molecules targeting nAChRs. Information is also given on their potential therapeutic activity.