Liu Q, Sikand P, Ma C, Tang Z, Han L, Li Z, Sun S, LaMotte R, and Dong X. The Journal of Neuroscience. 2012; 32(42):14532-7.
β-Alanine, a popular supplement for muscle building, induces itch and tingling after consumption, but the underlying molecular and neuralmechanisms are obscure. Here we show that, in mice, β-alanine elicited itch-associated behavior that requires MrgprD, a G-protein-coupled receptor expressed by a subpopulation of primary sensory neurons. These neurons exclusively innervate the skin, respond to β-alanine, heat, and mechanical noxious stimuli but do not respond to histamine. In humans, intradermally injected β-alanine induced itch but neither wheal nor flare, suggesting that the itch was not mediated by histamine. Thus, the primary sensory neurons responsive to β-alanine are likely part of a histamine-independent itchneural circuit and a target for treating clinical itch that is unrelieved by anti-histamines.