ABSTRACT
The transient receptor potential (TRP) channels were first described in Drosophila, in which photoreceptors carrying trp gene mutations exhibited a transient voltage response to continuous light stimulation. Mammalian TRP channels have six subfamilies including TRP canonical, TRP vanilloid, TRP ankyrin, TRP Melastatin, TRP polycystin, TRP mucolipin, with about 28 mammalian subfamily members, most of which have splicing variants. The skin is divided into three layers: first, the epidermis, the outermost layer of skin, provides a waterproof barrier and creates the skin tone. Second, the dermis, directly under the epidermis, contains tough connective tissue, hair follicles, and sweat glands. Third, the deeper subcutaneous tissue is made of fat and connective tissue. One of the major functions of the epidermal keratinocytes is to construct and maintain a water-impermeable barrier, the stratum corneum. In hairless mouse skin after tape stripping, TRPV1 activation by capsaicin delays barrier recovery, whereas capsazepine, a TRPV1 antagonist, blocks this delay.
