Urethane anaesthesia could partly mask antinociceptive effects of non-steroidal anti-inflammatory drugs: a spinal c-Fos protein study

Abstract

Urethane anaesthesia strongly reduced the peripheral edema (31±5 and 96±8% reduction of carrageenan-enhanced paw and ankle diameters, respectively; P<0.001 for both) and the spinal c-Fos protein expression (71±4% reduction of the number of c-Fos protein-labeled nuclei; P<0.001), 3 h after intraplantar injection of carrageenan in rats. In urethane anaesthetised rats, i.v. injection of racemic-flurbiprofen (0.3, 3 and 9 mg/kg) has weaker effects on carrageenan-evoked spinal c-Fos protein expression and peripheral edema than those previously described in the same inflammatory nociceptive model in awake rats.