Channels shown: TRPA1, TRPM8, TRPV4, TRPV3, TRPV1, TRPM3, ANO1, TRPV2 Cold-sensitive<unk> s give rise to the sensations of cooling, cold and freshness. In the cornea cold receptors are thought to respond with an increase in firing rate to cooling produced by evaporation of lacrimal fluid 'tears' and thereby to elicit a blink reflex. Other<unk> s will react to opposite triggers and give rise to heat and in some cases even burning sensations. This is often experienced when coming in contact with capsaicin, an active chemical commonly found in red chili peppers. When coming in contact with your tongue (or any internal surface), the capsaicin de-polarizes the nerve fibers, allowing sodium and calcium into the fibers. In order for fibers to do so, they must have a specific<unk> . The<unk>  reacting to capsaicin and other heat producing chemicals is known as TRPV1. In response to heat, the TRPV1 receptor opens up passages that allow ions to pass through, causing the sensation of heat or burning. TRPV1 also has a molecular cousin, TRPM8. Unlike TRPV1, TRPM8 produces cooling sensations as mentioned previously. Similar to TRPV1, TRPM8 responds to a certain chemical trigger by opening its ion pathways. In this case, the chemical trigger is often menthol or other cooling agents. Studies performed on mice determined that the presence of both these receptors allows for a gradient of temperature sensing. Mice lacking the TRPV1 receptor were still capable of determining areas significantly colder than on a heated platform. Mice lacking the TRPM8 receptor however, were not able to determine the difference between a warm platform and a cold platform, suggesting we rely on TRPM8 to determine cold feelings and sensations.
Thermoreceptor
Baroreceptor
Nociceptor
Neuropil
Acetylcholinesterase
Neuropeptide
Somatrem
Norepinephrine transporter