title: Role of 5-HT₁B/₁D receptors in the reduction of formalin-induced nociception and secondary allodynia/hyperalgesia produced by antimigraine drugs in rats.
abstract: OBJECTIVE
  The present study analyzed the potential antinociceptive effect of the antimigraine drugs sumatriptan, dihydroergotamine or methysergide in rats submitted to the formalin test. Moreover, by using selective antagonists, the role of 5-HT1B/1D serotonergic receptors was investigated in the antinociception induced by these antimigraine drugs.
  
  
  METHODS
  The formalin test was used to assess the nociceptive activity. Overt pain-like behavior (flinching, 1h) and evoked nociception (long-lasting secondary mechanical allodynia and hyperalgesia, 6 days) were determined in the same rat.
  
  
  RESULTS
  Ipsilateral, but not contralateral, pre-treatment (in μg/paw) with sumatriptan (10-300), methysergide (1-30) or dihydroergotamine (1-30) significantly prevented flinching behavior (at 1h) as well as secondary allodynia and hyperalgesia (at day 6) induced by formalin. Interestingly, the antinociceptive (flinching), antiallodynic and antihyperalgesic effects of sumatriptan were completely prevented by peripheral pre-treatment with selective antagonists at the 5-HT1B (SB 224289; 100) or 5-HT1D (BRL 15572; 100) receptors. In contrast, the acute antinociceptive effects of methysergide and dihydroergotamine were partially prevented by SB 224289 and BRL 15572. The antiallodynic and antihyperalgesic effects of both drugs were completely prevented by BRL 15572 and partially prevented by SB 224289. Given alone, SB 224289 or BRL 15572 did not modify per se the long-lasting secondary allodynia and hyperalgesia.
  
  
  CONCLUSIONS
  The above findings suggest that: (i) the antimigraine drugs sumatriptan, methysergide and dihydroergotamine reduce the acute and chronic nociception induced by formalin; and (ii) this antinociceptive effect results from activation of peripheral 5-HT1B/1D serotonergic receptors.
authors.affiliation: Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav), Sede Sur, México, D.F., Mexico.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Godínez-Chaparro
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: López-Santillán
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Argüelles
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Villalón
authors.forename: Vinicio
authors.initials: V
authors.lastname: Granados-Soto
mesh_terms: D059787:Acute Pain; D000818:Animals; D001713:Biphenyl Compounds / Q000627:therapeutic use; D059350:Chronic Pain; D004087:Dihydroergotamine / Q000627:therapeutic use; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D005260:Female; D005557:Formaldehyde / Q000633:toxicity; D006930:Hyperalgesia / Q000139:chemically induced / Q000378:metabolism*; D008784:Methysergide / Q000627:therapeutic use; D059226:Nociceptive Pain / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D010879:Piperazines / Q000627:therapeutic use; D010881:Piperidones / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D044302:Receptor, Serotonin, 5-HT1B / Q000502:physiology*; D044346:Receptor, Serotonin, 5-HT1D / Q000502:physiology*; D012702:Serotonin Antagonists / Q000627:therapeutic use*; D013141:Spiro Compounds / Q000627:therapeutic use; D018170:Sumatriptan / Q000627:therapeutic use
chemical_list: D001713:Biphenyl Compounds; D010879:Piperazines; D010881:Piperidones; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; C108518:SB 22489G; D012702:Serotonin Antagonists; D013141:Spiro Compounds; D005557:Formaldehyde; D004087:Dihydroergotamine; D018170:Sumatriptan; C108532:BRL 15572; D008784:Methysergide