Transient receptor potential ion channels

Transient receptor potential (TRP) channels play an important role in a diversity of sensory function, including taste, smell, hearing and perception of pain. This family comprises proteins with six transmembrane-spanning domains that are assembled either as homotetramers or heterotetramers to form non-selective cation channels permeable to calcium and sodium ions. There are at least six subfamilies, including TRPC (canonical), TRPM (melastatin), TRPV (vanilloid), TRPA (ankyrin), TRPML (mucolipin) and TRPP (polycystin) (Nilius et al. 2007). 

Arguably one of the most interesting targets in the past decade has been the family known as the transient receptor potential (TRP) channels (Figure 108.1). They compose a superfamily of ion channels that play important roles in the transmission... 

Of these receptor sites, it is the distinct subsets of thermoreceptors in combination with nociceptors that give the sensations of heat and cooling by chemical stimulus in the mouth. In mammals it is proposed that a set of ion channels, called transient receptor potential (TRP) channels, are the primary molecular transducers of thermal stimuli. One such molecular transducer is the vanilliod receptor (VRl) channel, which is an ion-gated channel that is activated by temperatures above 43°C and by chemical irritants, such as, capsaicin and acidic pH [34]. Vanilliod receptor. 

The molecules that transduce noxious heat or cold are members of the transient receptor potential (TRP) receptor family. TRP proteins (Table 57-2) form tetra-meric nonselective cation channels within the plasma membrane, allowing sodium and calcium ion influx [4]. The TRPV3 channel is activated at temperatures between 31 and39°C, TRPV1 at43°C, and TRPV2 at 52-55°C. The heat pain threshold in humans is 43°C, suggesting that... 

Clapham, D. E., Montell, C., Schultz, G. and Julius, D. International Union of Pharmacology. XLIII. Compendium of voltage-gated ion channels transient receptor potential channels. Pharmacol. Rev. 55 591-596,2003. 

Clapham DE et al Compendium of voltage-gated ion channels Transient receptor potential channels. Pharmacol Rev 2003 55 591. [PMID 14657417]... 

In the CNS, receptors at most synapses are coupled to ion channels, that is, binding of the neurotransmitter to the postsynaptic membrane receptors results in a rapid but transient opening of ion channels. Open channels allow ions inside and outside the cell membrane to flow down their concentration gradients. The resulting change in the ionic composition across the membrane of the neuron alters the postsynaptic potential, producing either depolarization or hyperpolarization of the postsynaptic membrane, depending on the specific ions that move and the direction of their movement. 

---