Odour receptors and the organisation of the olfactory system
In 2004 Richard Axel and Linda B. Buck were awarded a Nobel Prize for their work on the olfactory system, which is responsible for our sense of smell.
Although it had long been clear that a sense of smell is important in how the olfactory system works. Axel and Buck discovered a large family of 1000 genes (3% of all our genes) that code for around 1000 different types of olfactory receptors located in particular cells inside the nose.
Carrying out the majority of their work in mice, Axel and Buck showed that each olfactory receptor cell is extremely specialised, containing only one of the 1000 different types of olfactory receptor. In turn, each receptor responds to only a small variety of odorant – or smell – types. When stimulated, receptor cells of the same variety send messages through the nervous system to the same hub, or glomerulus, in the brain’s olfactory bulb. These messages are then sent to other parts of the brain, where signals from multiple types of receptor and glomeruli are combined, and form patterns of smells that can be recognised in future. Thanks to Axel and Buck, we now understand how our brains can recognise such an enormous variety of tastes and smells.