Sigma receptors are promising drug development targets for a host of neurological, psychiatric, oncological, immunological, cardiovascular, ophthalmological, and gastrointestinal disorders. They are structurally unique proteins that are distinct from classical G protein-coupled receptors, ionotropic receptors, or receptor tyrosine kinases. With two subtypes currently known, they modulate cell survival and excitability, and subserve many critical functions in the body. Endogenous ligands for these receptors are unknown, though current clues point to neurosteroids.

"This book provides an update on sigma receptors, and summarizes recent advances in the medicinal chemistry, molecular biology, and cell biology of sigma receptors. It describes the functional effects mediated by these receptors and the potential clinical implications of these actions. This information is put in a historical perspective to help newcomers to the field successfully navigate the confusing early history surrounding these proteins, and provides a launching point from which future studies and research directions can easily be developed. Major advances in our understanding of sigma receptors have been made during the past few years. This book will facilitate exciting new research that could lead to significant advances in the treatment of neurologic, psychiatric, cardiovascular, immunologic, and gastrointestinal disorders through a better understanding of sigma receptors."

Contributing Authors.- Preface.- s Receptors: Historical Perspective and Background.- Medicinal Chemistry: New Chemical Classes and Subtype Selective Ligands.- Irreversible s Compounds.- Pharmacophore Models for s1 Receptor Binding.- Cloning of s1 Receptor and Structural Analysis of its Gene and Promoter Region.- Site-Directed Mutagenesis.- s Receptor Modulation of Ion Channels.- Subcellular Localization and Intracellular Dynamics of s1 Receptors.- Intracellular Signaling and Synaptic Plasticity.- Modulation of Classical Neurotransmitter Systems by s Receptors.- s2 Receptors: Regulation of Cell Growth and Implications for Cancer Diagnosis and Therapeutics.- Cognitive Effects of s Receptor Ligands.- s Receptors and Schizophrenia.- Potential Role of s1 Ligands and Neurosteroids in Major Depression.- s Receptors and Drug Abuse.- s1 Receptors and Modulation of Opiate Analgesics.- s Receptors in the Immune System: Implications for Potential Therapeutic Intervention - an Overview.- s Receptors and Gastrointestinal Function.- Appendix.