Mechanisms of itch evoked by β-alanine - PubMed (original) (raw)

The response of DRG neurons to β-alanine is MrgprD-dependent. A, Approximately 12% of WT DRG neurons responded to β-alanine (β-ala; 1 m

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) with increased [Ca2+]i, whereas _MrgprD_−/− DRG neurons did not respond (number of neurons analyzed: WT, n = 282; KO, n = 212, n = 3 mice per genotype). The response to histamine was not impaired in _MrgprD_−/− neurons. The percentage of _MrgprD_−/− neurons responding to histamine (100 μ

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) was similar to that of WT neurons (>300 neurons analyzed, 3–4 mice per genotype). Error bars represent SEM. B, Representative traces of DRG neurons from MrgprD GFP/+ mice in calcium imaging assays. β-alanine only activated GFP+ neurons as monitored by increased [Ca2+]i with calcium imaging. β-alanine-sensitive neurons (black, green, and blue traces; n = 91) did not respond to histamine (His; 100 μ

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) or CQ (1 m

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), and histamine- and CQ-sensitive neurons (yellow, red, and orange traces) did not respond to β-alanine (>200 neurons from 3 mice). C, β-alanine (BA; 1 m

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) induced action potentials in DRG neurons. In WT DRG, β-alanine-sensitive neurons (as determined by calcium imaging, n = 8) fired action potentials upon repeated β-alanine treatment. In contrast, none of the neurons tested from _MrgprD_−/− mice showed any response to the drug (n = 7).