S1RA, a selective sigma-1 receptor antagonist, inhibits inflammatory pain in the carrageenan and complete Freund's adjuvant models in mice.
The therapeutic potential of S1RA (E-52862), a selective sigma-1 receptor (σ1R) antagonist, has been explored in experimental neuropathic pain, but not in inflammatory pain models. The present study investigated the effect of the intraperitoneal administration of S1RA on the hind paw withdrawal response to thermal and mechanical stimulation following an intraplantar injection of carrageenan (CARR) and complete Freund's adjuvant (CFA), which are two well-characterized models of acute and chronic inflammatory pain, respectively. S1RA fully reversed both mechanical [dose of drug that produced half of its maximal response (ED50)=35.9 and 42.1 mg/kg for CARR-induced and CFA-induced pain, respectively] and thermal (ED50=27.9 mg/kg, CARR) hypersensitivity, whereas ibuprofen (CARR, mechanical allodynia) and celecoxib (CARR, thermal hyperalgesia; CFA, mechanical allodynia) failed to reach maximum efficacy. Morphine also showed maximum efficacy in all tests. Unlike celecoxib and ibuprofen, which decreased paw volume significantly, CARR-induced paw oedema was not reduced by S1RA and morphine, thus suggesting that the antinociceptive effect of S1RA does not involve a major anti-inflammatory (antioedema) action. S1RA was devoid of efficacy when administered to σ1R knockout mice, thus suggesting the involvement of σ1R in the antinociceptive effects exerted by S1RA. We conclude that S1RA represents a promising novel analgesic therapy for inflammatory pain.
Drug Discovery and Preclinical Development, Esteve, Parc Científic de Barcelona, Barcelona, Spain.
Georgia
G
Gris
Manuel
M
Merlos
José M
JM
Vela
Daniel
D
Zamanillo
Enrique
E
Portillo-Salido
D000701:Analgesics, Opioid / Q000627:therapeutic use; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D002351:Carrageenan / Q000633:toxicity; D004195:Disease Models, Animal; D004487:Edema / Q000188:drug therapy / Q000209:etiology; D005620:Freund's Adjuvant / Q000633:toxicity; D006930:Hyperalgesia / Q000188:drug therapy; D007052:Ibuprofen / Q000627:therapeutic use; D007249:Inflammation / Q000139:chemically induced / Q000150:complications*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009020:Morphine / Q000627:therapeutic use; D009025:Morpholines / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D010147:Pain Measurement; D011720:Pyrazoles / Q000627:therapeutic use*; D017480:Receptors, sigma / Q000037:antagonists & inhibitors* / Q000172:deficiency / Q000235:genetics; D013997:Time Factors; D000097605:Sigma-1 Receptor
D000701:Analgesics, Opioid; D000894:Anti-Inflammatory Agents, Non-Steroidal; D002351:Carrageenan; D005620:Freund's Adjuvant; D007052:Ibuprofen; D009020:Morphine; D009025:Morpholines; D011720:Pyrazoles; D017480:Receptors, sigma; D000097605:Sigma-1 Receptor; C576663:4-(2-((5-methyl-1-(2-naphthalenyl)-1H-pyrazol-3-yl)oxy)ethyl)morpholine