Abstract:Ocular pruritus is one of the common symptoms of ocular surface diseases. People know little about the mechanism of ocular pruritus. In clinical practice, eye drops can only be used to relieve eye discomfort. Eye itch often makes patients feel extremely painful and uncomfortable. The itch is afferent from primary neurons, mainly small-diameter unmyelinated afferent neuron fibers, whose cell bodies are located in the dorsal root ganglia or trigeminal ganglia. These neurons transmit the itch from the skin to the central nervous system. In the spinal cord, these afferent nerves synapse with secondary neurons in the dorsal horn and send signals to the brain. Pruritus sensory neurons are generally considered to be a subgroup of pain neurons. Intensity coding theory suggests that at low emissivity, neuronal activity can cause the sensation of itching. With the advancement of molecular biology and neuroscience technology, it was discovered that one of the main functions of Mrgpr(mas-related G protein-coupled receptor)protein is pruritus, and most of Mrgprs(all MrgprA, MrgprB and MrgprC subfamily members, and MrgprD)are almost exclusively expressed in specific dorsal root and trigeminal ganglion neurons. This review will introduce the mechanism and signal pathways of ocular pruritus, as well as the role of Mrgpr protein in ocular pruritus, and provide help for the treatment of ocular pruritus.
