Thermo-TRP Channels in Pain Sensation: An Overview

The perception of temperature is a major component of sensory experience of animal and human
organisms. A sensitive response of the nervous system to changes in temperature is of predominant
importance for homeo-therms to maintain a stable body temperature. Recent investigations in central
and peripheral thermosensitivity have emphasized the importance of temperature-activated transient
receptor potential (TRP) cation channels and they are being ardently pursued as targets for analgesic
drug discovery. They are the largest group of sensory detectors expressed in nerve terminals and
pain receptors activated by temperature and provide information about thermal changes in the
environment. These temperature sensitive or thermo-TRP channels (TRPA1, TRPM8, TRPV1,
TRPV2, TRPV3 and TRPV4) have been characterized to date that exhibit sensitivity to increases or
decreases in temperature as well as to chemical substances that elicit similar hot or cold sensations.
The thermal thresholds of many thermo-TRP channels are known to be modulated by extracellular
mediators, released by tissue damage or inflammation. Antagonists or blockers of these channels are
likely as promising targets for new analgesic drugs at the periphery and central levels and thus,
controlling the modulation of thermo-TRP channels by inflammatory mediators and ligands may be a
useful alternative strategy in developing novel analgesics.