Selective 5-HT7 receptor agonists LP 44 and LP 211 elicit an analgesic effect on formalin-induced orofacial pain in mice

Authors

  • Kadriye DEMİRKAYA Gulhane Medical Academy; Department of Restorative Dentistry and Endodontics
  • Özlem Martı AKGÜN Gulhane Medical Academy; Department of Pediatric Dentistry
  • Buğra ŞENEL Gulhane Medical Academy; Department of Dentomaxillofacial Radiology
  • Zeynep ÖNCEL TORUN Gulhane Medical Academy; Department of Restorative Dentistry and Endodontics
  • Melik SEYREK Gulhane Medical Academy; Department of Pharmacology and Pain Research Centre
  • Enza LACİVİTA Università degli studi di Bari Aldo Moro; Dipartimento di Farmacia – Scienze del Farmaco
  • Marcello LEOPOLDO Università degli studi di Bari Aldo Moro; Dipartimento di Farmacia – Scienze del Farmaco
  • Ahmet DOĞRUL Gulhane Medical Academy; Department of Pharmacology and Pain Research Centre

DOI:

https://doi.org/10.1590/1678-775720150563

Abstract

The most recently identified serotonin (5-HT) receptor is the 5-HT7 receptor. The antinociceptive effects of a 5-HT7 receptor agonist have been shown in neuropathic and inflammatory animal models of pain. A recent study demonstrated the functional expression of 5-HT7 receptors in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis, which receives and processes orofacial nociceptive inputs. Objective To investigate the antinociceptive effects of pharmacological activation of 5-HT7 receptors on orofacial pain in mice. Material and Methods Nociception was evaluated by using an orofacial formalin test in male Balb-C mice. Selective 5-HT7 receptor agonists, LP 44 and LP 211 (1, 5, and 10 mg/kg), were given intraperitoneally 30 min prior to a formalin injection. A bolus of 10 µl of 4% subcutaneous formalin was injected into the upper lip of mice and facial grooming behaviors were monitored. The behavioral responses consisted of two distinct periods, the early phase corresponding to acute pain (Phase I: 0–12 min) and the late phase (Phase II: 12–30 min). Results LP 44 and LP 211 (1, 5, and 10 mg/kg) produced an analgesic effect with reductions in face rubbing time in both Phase I and Phase II of the formalin test. Conclusion Our results suggest that 5-HT7 receptor agonists may be promising analgesic drugs in the treatment of orofacial pain.

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Published

2016-06-01

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Section

Original Articles