Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sensory neuron-specific G protein coupled receptors (SNSRs) have been described as a family of receptors whose expression in small diameter sensory neurons in the trigeminal and dorsal root ganglia suggests an implication in nociception. To date, the physiological function(s) of SNSRs remain unknown. Hence, the aim of the present study was to determine the effects of rat SNSR1 activation on nociception in rats. The pharmacological characterization of rat SNSR1 was initially performed in vitro to identify a specific ligand, which could be used subsequently in the rat for physiological testing. Among all ligands tested, gamma2-MSH was the most potent at activating rat SNSR1. Structure-activity relationship studies revealed that the active moiety recognized by rat SNSR1 was the C-terminal part of gamma2-MSH. The radiolabeled C-terminal part of gamma2-MSH, gamma2-MSH-6-12, bound with high affinity to membranes derived from rat skin and spinal cord, demonstrating the presence of receptor protein at both the proximal and distal terminals of dorsal root ganglia. To investigate the physiological role of SNSR, specific ligands to rat SNSR1 were tested in behavioral assays of pain sensitivity in rats. Selective rat SNSR1 agonists produced spontaneous pain behavior, enhanced heat and mechanical sensitivity when injected intradermally, and heat hypersensitivity when injected centrally, consistent with the localization of rat SNSR1 protein at central and peripheral sites. Together, these results clearly indicate that the SNSR1 plays a role in nociception and may provide novel therapeutic opportunities for analgesia.
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PMID:Sensory neuron-specific receptor activation elicits central and peripheral nociceptive effects in rats. 1511 1

Sensory neuron-specific receptors (SNSRs) belong to a large family of GPCRs, known as Mrgs (Mas-related genes), many of which are preferentially expressed in primary afferent nociceptors. Selective SNSR agonists produce pain-like behaviors in rats, showing that SNSR activation is sufficient to produce pain. However, it is unknown whether SNSR activation is necessary for pain either in the normal condition or in pathological pain states. Here we used small interfering RNA (siRNA) to acutely knockdown rat SNSR1 and test the hypothesis that this receptor mediates pain responses. Administration of siRNA to the lumbar spinal cord in rats dose-dependently knocked down rSNSR1 mRNA and protein and abolished heat hyperalgesia evoked by intradermal administration of specific rSNSR1 agonists. In rats with levels of rSNSR1 knockdown sufficient to block responses to the SNSR1 agonists, there was no effect on normal pain responses, but there was a significant reduction of heat hyperalgesia in an inflammatory pain model (Complete Freund's Adjuvant), supporting a role for rSNSR1 in inflammatory pain. Further in vivo studies revealed that SNSR1 knockdown had no effect on responses to intradermal capsaicin, a selective TRPV1 agonist. In contrast, a selective TRPV1 antagonist abolished heat hyperalgesia produced by an SNSR agonist, suggesting that TRPV1 receptors mediate rSNSR1-evoked responses. We also found that rSNSR1-like immunoreactivity, like TRPV1, is localized in the superficial dorsal horn of the spinal cord. We propose that rSNSR1 represents a new member of the receptors expressed on chemosensitive nociceptors responsible for detecting the "inflammatory soup" of mediators generated by tissue damage.
Pain 2009 May
PMID:Role of rat sensory neuron-specific receptor (rSNSR1) in inflammatory pain: contribution of TRPV1 to SNSR signaling in the pain pathway. 1930 60