odorantreceptor

An odorant receptor is a protein found on the surface of olfactory receptor neurons. These neurons are located in the olfactory epithelium of the nasal cavity. Odorant receptors are part of the G protein-coupled receptor (GPCR) superfamily, a large group of cell surface receptors involved in signal transduction. There are hundreds of different types of odorant receptors in humans, and even more in some other animals like rodents. Each olfactory receptor neuron typically expresses only one type of odorant receptor.

When an odorant molecule, a volatile chemical, binds to a specific odorant receptor, it triggers a cascade of intracellular events. This binding activates a G protein, which in turn activates an enzyme called adenylyl cyclase. Adenylyl cyclase then produces cyclic AMP (cAMP), a second messenger molecule. cAMP opens ion channels, leading to a change in the electrical potential of the neuron. This electrical signal is then transmitted to the brain, where it is interpreted as a specific smell. The combinatorial code of activation across different odorant receptors allows for the perception of a vast array of odors.