The largest group of receptors that function as noxious stimuli detectors in nociceptors is the transient receptor potential (TRP) channel family. TRPs have been subclassified into the C, V, M, A, P, and ML subfamilies. The members are principal transducers of thermal stimuli that depolarize nerve terminals to the action potential threshold. A role of TRP channels specifically in pain and thermosensation was first suggested by the finding that mammalian TRPV1 is activated by both noxious heat and capsaicin, the active ingredient of chilli peppers. Although there is little amino-acid conservation among distant TRP channels, they share a similar architecture of six-transmembrane domains with cytoplasmic amino and carboxy termini. TRP channels are thought to function as tetramers, mostly as homomers. Six of the 28 TRP channels from the three distinct TRP family subtypes are activated by temperature (TRPV1–4, TRPM8 and TRPA1). Three other TRP channels (TRPM2, TRPM4 and TRPM5) are strongly modulated by warm temperatures as well; however, the lack of expression in nociceptor neurons argues against a role in nociception[1].