Inflammation Research

, Volume 51, Issue 5, pp 219–222

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

Authors

  • G. Pinardi
    • Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Casilla 70000, Santiago 7, Chile, Fax: ++ 56 2 737 2783, e-mail: gpinardi@machi.med.uchile.cl
  • F. Sierralta
    • Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Casilla 70000, Santiago 7, Chile, Fax: ++ 56 2 737 2783, e-mail: gpinardi@machi.med.uchile.cl
  • H. F. Miranda
    • Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Casilla 70000, Santiago 7, Chile, Fax: ++ 56 2 737 2783, e-mail: gpinardi@machi.med.uchile.cl

DOI: 10.1007/PL00000296

Cite this article as:
Pinardi, G., Sierralta, F. & Miranda, H. Inflamm. res. (2002) 51: 219. doi:10.1007/PL00000296

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.

Key words: Ketoprofen - Diclofenac - Piroxicam - Paracetamol - α-adrenoceptors

Copyright information

© Birkhäuser Verlag, 2002