Neuronal nicotinic receptors and their implications in ageing and neurodegenerative disorders in mammals.

Recent biochemical, molecular biology and pharmacological studies have revealed the existence of multiple functional subtypes of neuronal nicotinic receptor in the rodent as well as in the human CNS. An important goal in this research is to define the physiological role of these receptors and to understand the mechanisms by which these receptors interact with other receptors and neurotransmitters. Nicotinic receptors are detectable in the immature rat brain. Exposition of various agents can change the expression of receptors. Neuronal receptors undergo changes during ageing, the pattern of which is different for various subtypes of nicotinic receptor. Neurodegenerative disorders, such as Alzheimer's disease, are characterized by losses in this type of receptor. An increased understanding of underlying mechanisms leading to this disease will provide pathophysiological knowledge and strategies for treatment. Imaging techniques such as positron emission tomography provide a possible means of tracing the nicotinic receptor in vivo in patients with Alzheimer's disease.