A rapid pain response to extreme temperatures is of vital importance to prevent being burned by touching a hot object or accidentally swallowing scolding soup, for example. Sensory nerves throughout the body – including in our skin and mucous membranes – detect temperature. In people who suffer from certain conditions, such as infections or nerve damage, these nerves become extra sensitive. This sometimes results in oversensitivity to innocuous temperatures and chronic pain.
There are ion channels in the cell wall around these nerves – microscopic sluices that react to certain stimuli and then send electrical signals to the brain. Approximately ten years ago, American researchers discovered the capsaicin receptor: an ion channel that is responsible for the detection of heat and of “hot” chemical substances. Capsaicin is the substance that gives red peppers their spicy taste. Research demonstrated, however, that the capsaicin receptor is not responsible for all heat detection and that there must be other molecular detectors for extreme heat.
Research conducted by Dr Joris Vriens, in collaboration with colleagues at the Leuven Laboratory for Ion Channel Research and German researchers, has demonstrated that the ion channel TRPM3 is also a molecular sensor for heat and for the hormone pregnenolone sulfate – a precursor to the gender hormones oestrogen or testosterone. Mice with a defective TRPM3 gene appear to feel far less pain when exposed to heat or the steroid hormone. Moreover, these mice do not develop oversensitivity to heat when they have infections. These new discoveries make TRPM3 a promising target for the development of new analgesic medications.
The complete text of the "TRPM3 is a nociceptor channel involved in the detection of noxious heat” by Joris Vriens, Grzegorz Owsianik, Thomas Hofmann, Stephan Philipp, Julia Stab, Xiaodi Chen, Melissa Benoit, Fenqin Xue, Annelies Janssens, Sara Kerselaers, Johannes Oberwinkler, Rudi Vennekens, Thomas Gudermann, Bernd Nilius and Thomas Voets is available on the website of the scientific journal Neuron