ArticleScientific reports2022
Amelioration of injury-induced tissue acidosis by a nonsteroidal analgesic attenuates antinociceptive effects of the pH-dependent opioid agonist NFEPP.
Article in Scientific reports, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.
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Who cites it
3 citing papers in PubMed, 6 citations in OpenAlex.
- Emerging therapeutic approaches for treating abdominal pain.Journal of the Canadian Association of Gastroenterology · 2025Review
- Effects of pH on opioid receptor activation and implications for drug design.Biophysical journal · 2024Review
- Activation of the Calcium-Sensing Receptor by a Subfraction of Amino Acids Contained in Thyroid Drainage Fluid.ACS pharmacology & translational science · 2024Article
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Authors and funding
5 authors at 1 institution in 1 country.
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No grant is acknowledged in the PubMed record.
Abstract
Opioid agonists are powerful drugs for managing pain. However, their central side effects are limiting their use and drugs with similar potency, but a lower risk profile are needed. (±)-N-(3-fluoro-1-phenethylpiperidine-4-yl)-N-phenylpropionamide (NFEPP) is a novel opioid agonist that preferentially activates opioid receptors at acidic extracellular pH. NFEPP was designed to activate peripheral opioid receptors in injured tissue, therefore precluding side effects elicited at normal pH in brain or intestinal wall. Considering the common combination of opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) in multimodal analgesia, we investigated the interaction between NFEPP and a widely prescribed prototypical NSAID, diclofenac (DCF), in a rat model of unilateral hindpaw inflammation induced by complete Freund's adjuvant. We evaluated the effects of systemically applied DCF on the paw tissue pH, on the expression of inflammatory mediators in immune cells from inflamed paws and on the expression of opioid receptors in dorsal root ganglia. Additionally, we investigated the antinociceptive efficacy of NFEPP injected into the inflamed paws after DCF treatment. We found that DCF reduced inflammation-induced nociceptive responses and tissue acidosis, but did not change the mRNA expression of IL-1β, TNF-α, IL-6, IL-4, NGF, or of mu-, delta-, or kappa-opioid receptors. The treatment with DCF moderately reduced the antinociceptive efficacy of NFEPP, suggesting a correlation between an increase in local tissue pH and the decreased antinociceptive effect of this pH-sensitive opioid agonist.
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