Transient receptor potential channel ligands

Fig. 1 Transient receptor potential vaniUoid 1 (TRPVl) and other transient receptor potential channels expressed in primary sensory neurons and their regulation by inflammatory mediators and exogenous or putative endogenous ligands, NFG nerve growth factor, PAR protease activated receptor 2, B2 bradykinin B2 receptor, ASIC acid-sensing ion channel, EPl/2 prostanoid E receptor...

Vitamin D-mediated transcellular calcium transport also involves entry and extmsion. Calcium influx from the intestine or bone is propelled by a steep electrochemical gradient mediated by the superfamily of Transient Receptor Potential (TRP) ion channels noted above. TRP channel ion selectivity and mode of activation are extremely variable. Some are activated or regulated by ligands such as amino acid amines or small peptides, others by physical stimuli (e.g., heat), and still others by as yet unknown mechanisms. All TRP channels are Ca2+ and Na+ selective, but the selectivity for Ca2+ versus Na+ (Ca/Na ratio) varies enormously from >100 1, to <0.05 1. This variability has contributed to a confusing TRP channel nomenclature. 

In addition to actions at cannabinoid receptors, AEA, 2AG, virodhamine, noladin ether, and NADA also act at the vanilloid receptor (transient receptor potential vanilloid type 1 TRPV1 previously know as VRl), a ligand-gated ion channel that is a member of the transient receptor potential (TRP) ion channel family (recently reviewed by Di Marzo et al. 2002). In addition, zl -THG and cannabinol at high (20 pM) concentrations have recently been identified as agonists at another TRP, the ANKTMl channel (Jordt et al. 2004). These findings raise the possibility that the TRP channels maybe ionotropic cannabinoid receptors. 

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