Molecular Biology of the Nociceptor/Transduction

Pain is initiated by the activation of specialized sensory neurons called nociceptors. These neurons are called upon to detect and report on a wide array of potentially injurious stimuli in a manner appropriate to the physical nature and intensity of these stimuli. In this chapter, we describe characteristic anatomical and physiological features of the nociceptor that shape their sensory and output properties. We next describe several major classes of cell-surface proteins - ion channels, neurotrophin receptors, and G protein-coupled receptors - that account for many of the sensory and signaling functions of nociceptors. We also discuss how molecular polymodality, molecular redundancy, and molecular interaction contribute to emergent properties of nociceptive neurons. Finally, we illustrate how specific changes in expression levels, subcellular localization, and functional properties of the components of the nociceptor molecular toolbox can contribute to pathological pain in the context of inflammation and nerve injury.