Localization of neuropeptides by radioimmunoassay

The past half-century has seen an enormous development in the area of biomedical science. This includes also research related to neuroactive peptides. These compounds have been the subject for extensive studies in many cases resulting in knowledge opening for new therapeutic strategies for the management of various neurological disorders. In this research the radioimmunoassay has represented an invaluable tool. This method, first introduced for the assessment of serum and plasma levels of various hormones, meant a transition from bioassay to a more sensitive and precise technique for protein and peptide quantification in samples of clinical relevance. It accounts for an approach which became one of the most widely used methods in routine and research at many clinical and basic laboratories. This relatively simple technique also became a worthwhile instrument in most studies exploring the field of neuropeptides. In this chapter, various approaches to probe neuroactive peptides in tissues and biological fluids are reviewed. It is by no means exhaustive and does cover all aspects of radioimmunoassay, but it serves to give the readers an idea about some essential principles of the practical use of this technique for probing peptides in the above-mentioned compartments.