TRP Channels and Pruritus

Itch (pruritus) is one of the most often seen sensory phenomena in clinical practice. Recent neurophysiological findings proposed the existence of a novel pruriceptive system which includes a multitude of pruritogenic (itch-inducing) peripheral mediators, itch-selective pruriceptors, sensory afferent networks, spinal cord neurons, and certain central nerv- ous system regions. In this review, we first introduce major features of the pruriceptive system. We then focus on defining the roles of transient receptor potential (TRP) ion channels in skin-coupled itch and provide compelling evidence that cer- tain thermosensitive TRP channels (especially TRPV1, TRPV3, TRPV4, and TRPA1) are indeed key players in pruritus pathogenesis. Finally, we propose TRP-centered future experimental directions towards the therapeutic targeting of TRP channels in the clinical management of itch.