Transient receptor potential channels (TRP) are non-selective calcium permeant cation channel located mostly on the plasma membrane of numerous animal cell types. They are involved in osmotic sensitivity and mechano-sensitivity. The exposure to hypotonicity within the physiological range induces some TRP channels activation exhibiting an outward rectification. TRP channels can also be activated by heat, low pH, citrate and phorbol esters. The increase of intracellular Ca2+ potentiates TRP channel currents. TRP Channels play an obligatory role as a molecular component in the nonselective cation channel activation induced by 4-alpha-phorbol 12,13-didecanoate and hypotonic stimulation in synoviocytes and also regulates production of IL-8.