Glycine Receptors are Present in Human Epidermis

Abstract

The inhibitory glycine receptor (GlyR) is a member of the nicotinoid receptor superfamily. This heteropentameric Cl- channel is composed of different α (1-4) and a β-subunit and mediates fast synaptic transmission in the central nervous system. Since glycine, the natural ligand of GlyR has been found to enhance epidermal barrier recovery; we aimed at characterizing GlyR distribution in human skin and their function in skin physiology. We detected different α- subunits and the β- GlyR subunit on mRNA and protein level in human skin and cultured keratinocytes and fibroblasts. In cultured human keratinocytes but not in fibroblasts, glycine induced proliferation. Epidermis-equivalents were significantly thicker than control if cultured in the presence of glycine. In human skin, GlyR immunoreactivity (IR) was detected in the upper epidermal layers. In eczema and psoriasis, GlyR IR was reduced in areas with parakeratosis suggesting a role of GlyR in terminal differentiation and epidermal barrier control.