Grundy, L.Caldwell, A.Garcia-Caraballo, S.Grundy, D.Spencer, N.J.Dong, X.Castro, J.Harrington, A.M.Brierley, S.M.2021-06-302021-06-302021Journal of Neuroscience, 2021; 14(17):3900-39160270-64741529-2401http://hdl.handle.net/2440/131004Understanding the sensory mechanisms innervating the bladder is paramount to developing efficacious treatments for chronic bladder hypersensitivity conditions. The contribution of Mas-gene-related G protein-coupled receptors (Mrgpr) to bladder signaling is currently unknown. Using male and female mice, we show with single-cell RT-PCR that subpopulations of DRG neurons innervating the mouse bladder express MrgprA3 (14%) and MrgprC11 (38%), either individually or in combination, with high levels of coexpression with Trpv1 (81%-89%). Calcium imaging studies demonstrated MrgprA3 and MrgprC11 agonists (chloroquine, BAM8-22, and neuropeptide FF) activated subpopulations of bladder-innervating DRG neurons, showing functional evidence of coexpression between MrgprA3, MrgprC11, and TRPV1. In ex vivo bladder-nerve preparations, chloroquine, BAM8-22, and neuropeptide FF all evoked mechanical hypersensitivity in subpopulations (20%-41%) of bladder afferents. These effects were absent in recordings from Mrgpr-clusterD2/2 mice. In vitro whole-cell patch-clamp recordings showed that application of an MrgprA3/C11 agonist mixture induced neuronal hyperexcitability in 44% of bladder-innervating DRG neurons. Finally, in vivo instillation of an MrgprA3/C11 agonist mixture into the bladder of WT mice induced a significant activation of dorsal horn neurons within the lumbosacral spinal cord, as quantified by pERK immunoreactivity. This MrgprA3/C11 agonist-induced activation was particularly apparent within the superficial dorsal horn and the sacral parasympathetic nuclei of WT, but not Mrgpr-clusterD2/2 mice. This study demonstrates, for the first time, functional expression of MrgprA3 and MrgprC11 in bladder afferents. Activation of these receptors triggers hypersensitivity to distension, a critically valuable factor for therapeutic target development.en© 2021 the authors. Authors grant JNeurosci a license to publish their work and copyright remains with the author. For articles published after 2014, the Society for Neuroscience (SfN) retains an exclusive license to publish the article for 6 months; after 6 months, the work becomes available to the public to copy, distribute, or display under the terms of the Creative Commons Attribution 4.0 International License (CC-BY). This license allows data and text mining, use of figures in presentations, and posting the article online, provided that the original article is credited.Bladder; GPCR; itch; pain; sensory neurons; visceral afferentsJournal article100003883810.1523/jneurosci.0033-21.20210006454106000022-s2.0-85105836827571161Castro, J. [0000-0002-5781-2224]Harrington, A.M. [0000-0002-1562-4137]Brierley, S.M. [0000-0002-2527-2905]