Function and Regulation of Chemoreceptors

Book excerpt: To perceive environmental chemical compounds and to convert these external signals into an intracellular message might be the oldest way for a living being to get information from the outside world. Chemoreceptors are proteins or protein complexes that detect molecules from the outside world either at distance (olfaction) or at close range (gustation). Chemoreceptors can operate as ionotropic or as metabotropic receptors. Ionotropic receptors form ion channels that are activated via ligand binding. Activation of a metabotropic receptor initiates an intracellular signaling cascade that could include a change of enzymatic activity, production of second messenger or activation of ion channels. The receptor performance has to be fine-tuned according to the actual physiological requirements and the presentation of the chemical signal. This Research Topic collects reports and reviews on structure and function of chemoreceptors in the animal kingdom, and how these receptors are regulated.