A mouthful of your mum’s lasagne does more than just fill your stomach – it satisfies your brain. Signals to the brain start with the very first mouthful and with that most important of organs: the tongue. Within the tongue’s taste buds are different types of taste receptor cells, two of which from a mouse tongue are shown in red and green. These receptor cells detect the five tastes – bitter, sweet, salty, sour and umami (Japanese for savoury) – and then signal to the gustatory nerves, which link to the brain. The identity of the signal, scientists have discovered, is a molecule called ATP, more commonly used by cells as an energy source. After its release from receptor cells, ATP activates the gustatory nerves and almost immediately gets degraded. This degradation switches off the signal, thus allowing the tongue and the brain to detect all the flavours of the next delicious mouthful.
Written by Ruth Williams
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