Adrenergic mechanisms in antinociceptive effects of non steroidal anti-inflammatory drugs in acute thermal nociception in mice

G. Pinardi, F. Sierralta, H. F. Miranda

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

Objective: The interactions of α-adrenoceptors with the antinociceptive effects of non-steroidal anti-inflammatory drugs (NSAIDs) were assessed in acute thermal nociception in mice. Materials and methods: The analgesic effect was analyzed by the tail-flick test. Results: The pretreatment with yohimbine (1 mg/kg i.p.), 30 min prior to the intraperitoneal injection of ketoprofen (50 mg/kg), diclofenac (30 mg/kg) and piroxicam (50 mg/kg) antagonized the antinociception induced by these NSAIDs, significantly reducing the tail-flick latency. Yohimbine did not affect paracetamol (125 mg/kg) induced antinociception. Prazosin (1 mg/kg i.p.) antagonized only the effect of paracetamol, without affecting the latency of the other drugs. When NSAIDs were administered i.t. (ketoprofen 2 m/kg; diclofenac 0.9 mg/kg; piroxicam 1.5 mg/kg; paracetamol 3.75 mg/kg), the same results were obtained after i.p. pretreatment with yohimbine and prazosin. The pretreatment of phenoxybenzamine (1 mg/kg i.p.) antagonized all antinociceptive effects. Conclusions: NSAIDs induced antinociception in an acute thermal pain model without inflammation. The mechanism of antinociception induced by ketoprofen, diclofenac and piroxicam involves an activation of α2-adrenoceptors at spinal and supraspinal levels, while paracetamol-induced antinociception is probably due mainly to central activation of the descending noradrenergic inhibitory system by α1-adrenoceptors.

Original languageEnglish
Pages (from-to)219-222
Number of pages4
JournalInflammation Research
Volume51
Issue number5
DOIs
Publication statusPublished - 2002

Keywords

  • Diclofenac
  • Ketoprofen
  • Paracetamol
  • Piroxicam
  • α-adrenoceptors

ASJC Scopus subject areas

  • Immunology
  • Pharmacology

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