Module 10: Figure inflammatory soup

Signalling mechanisms operating in the skin to induce pain stimuli in endings of the sensory neurons.

The endings of sensory neurons have a dual function in nociception in that they not only have receptors to detect noxious stimuli, but they can also release agents such as substance P and calcitonin gene-related peptide (CGRP) that contribute to the sensation of pain. The detection of a range of noxious stimuli (thermal, mechanical or chemical) is carried out by a variety of ion channel receptors (TRPA1, TRPV1, TRPM8 and P2X3) that respond to a great number of painful stimuli present in the local environment that has been referred to as an ‘inflammatory soup’ (central red region).