To analyze in a population from Argentina the variation of three genes involved in the control of pain pathways-two genes that code for opioid receptors (OPRM1 and OPRK1) and COMT, which codes for an important enzyme in the control of neurotransmission-and to evaluate the associations of these genes with oral pain and the need for analgesics in the population under study.
Kappa opioid receptor antagonists may therefore represent novel therapies for neuropathic pain by targeting aversive aspects of ongoing pain while preserving protective functions of acute pain.
This study demonstrates the efficacy of KOR agonists in the treatment of bone cancer-induced pain in mice, without changing tumor size or proliferation in cancer cell lines.
Neither nalfurafine nor any other KOR agonist is currently approved anywhere for treatment of pain, but recent evidence suggests that G protein signaling-biased KOR agonists may have promise as candidate analgesics/antipruritics with reduced side effects compared to nonbiased or ß-arrestin-signaling-biased KOR agonists.
Several studies have shown that agonists that activate the κ-opioid receptor (KOR) in a manner that favors G protein coupling over β-arrestin2 recruitment in cell culture may represent a means to treat pain and itch while avoiding sedation and dysphoria.
The aim of this study was to investigate if genetic variants of mu, kappa, and delta opioid receptor genes (OPRM1, OPRK1, and OPRD1) and the catechol-O-methyltransferase gene (COMT) influenced the pain phenotype in patients with osteoarthritis.
In contrast to their role in inflammatory pain aversion, EP3 receptors on serotonergic cells were dispensable for acute nociceptive behaviors and for aversion induced by thermal pain or a κ opioid receptor agonist.
A recent study has demonstrated that a G protein-biased agonist for κ-OR provides effective pain and itch relief without causing sedation or dysphoria, in animal models.
In the present study, the possible influence of polymorphisms in three opioid receptor (OPRM, OPRD and OPRK) genes and the catechol-O-methyltransferase (COMT) gene on pain sensitivity in healthy participants was investigated.
Pairwise tag single nucleotide polymorphisms (SNPs) in DREAM, PDYN and OPRK1 were genotyped in a UK population-based discovery cohort in whom pain was assessed using blank body manikins at three time points.
The recently shown efficacy of these analgesics combined with a possible lower abuse potential and side effect burden than mu opioid receptor agonists makes delta and peripherally restricted kappa opioid receptor agonists promising targets for treating pain.
Regarding the relationship between the expression of kappa-opioid receptor mRNA and the symptoms in RA patients, it was noted that the expression of the receptor mRNA was significantly decreased in RA patients in whom erythrocyte sedimentation rate (ESR), Lansbury index, and visual analogue pain scores were high.