Table 1.
ThermoTRP | Thermal activation | Chemical agonist | Sensory neuron/skin expression | Temperature phenotype of null mutant |
---|---|---|---|---|
TRPV1 | > 42°C | capsaicin, acidic pH, camphor, ethanol, resiniferatoxin, 2-APB piperine, eugenol, gingerol, VaTx1-3 (spider toxin) | sensory neuron | impaired thermal avoidance and hyperalgesia |
TRPV2 | > 52°C | 2-APB camphor, menthol, thymol, carvacrol, eugenol, 2-APB | sensory neuron | not reported |
TRPV3 | > 33°C | keratinocytes/sensory neuron? | impaired thermotaxis and thermal avoidance. | |
TRPV4 | > 25–34°C | 4αPDD, bisandrographolide | keratinocytes/sensory neuron | impaired thermotaxis, thermal avoidance, and hyperalgesia |
TRPM2* | > 35°C | H2O2, ADP-ribose, βNAD | not reported | not reported |
TRPM4* | heat** | cytosolic Ca2+ | not reported | not reported |
TRPM5* | heat** | cytosolic Ca2+ | not reported | not reported |
TRPM8 | < 25°C | menthol, icilin, l-carvone eucalyptol, isopulegol, geraniol, linalool | sensory neuron | impaired cold sensation |
TRPA1 | < 17°C | cinnamaldehyde, mustard oil, eugenol, icilin, allicin, acrolein methyl salicylate, gingerol, GsMTx-4 (spider toxin), etc. | sensory neuron |
TRPM2, TRPM4 and TRPM5 are temperature sensitive; however, evidence for their expression in DRG or skin is lacking [28,72]. The expression of TRPM5 in taste cells however suggests a potential explanation for the intriguing observation that temperature can affect taste perception [72].
Activity of TRPM4 and TRPM5 is increased by heating but thermal activation thresholds have not been determined.