Neuroscience Perspectives provides multidisciplinary reviews of topics in one of the most diverse and rapidly advancing fields in the life sciences. Whether you are a new recruit to neuroscience, or an established expert, look to this series for 'one-stop' sources of the historical, physiological, pharmacological, biochemical, molecular biological and therapeutic aspects of chosen research areas. The sigma receptor was originally thought to be a subset of the opioid receptor family, and it is less than 10 years since it was recognized that this receptor represents unique binding sites in mammalian brain and peripheral organs, distinct from any other known neurotransmitter receptor. Since the sigma receptors exhibit high affinity for members of diverse classes of psychotropic drugs, and have been postulated to be involved in various central nervous disorders, neuroscientists have demonstrated a great deal of interest in the elucidation of these receptor sites and their biological relevance. Relatively little is known about the precise role of sigma receptors in normal brain function and in CNS disorders, despite an overwhelming research effort. This research has resulted in many controversies, some of which have been reconciled while others have not. This volume aims to update the reader on the current situation, and deals with the potential functional significance of these receptors in the brain and peripheral organs and, where appropriate, makes reference to the clinical potential of these sites.