| Abstract: | To evaluate the effectiveness of piroxicam, a clinically effective, long-acting, nonsteroidal antiinflammatory drug, in a potential animal model of chronic nociception, the locomotor activity of arthritic rats was monitored over long periods of time by computer. Rats injected with complete Freund's adjuvant (CFA) displayed locomotor deficits as measured by both horizontal and vertical activity. In experiment 1, to test the effectiveness of piroxicam therapy in severely arthritic animals, administration of piroxicam (1--10 mg/kg/day) was initiated 14 days after CFA injection and activity was recorded for 5 days. It was found that a single treatment significantly increased the mobility of the arthritic animals and the 4 additional days of treatment induced continued improvement in mobility and reduction in paw swelling. In experiment 2, to assess the effect of piroxicam on the development of the immobility associated with CFA-induced arthritis, piroxicam administration (0.3--3.3 mg/kg/day) was initiated prior to CFA injection and locomotor activity was monitored for 16 days. It was demonstrated that the activity of CFA-injected rats severely and progressively decreased and that piroxicam significantly increased the activity of the arthritic rats, while having no effect on the activity of the nonarthritic control animals. These studies demonstrate the efficacy of piroxicam in arthritic rats and, although further investigation is necessary, demonstrate that the measurement of locomotor activity in arthritic rodents may be an important tool for the identification and evaluation of antiinflammatory/analgetic agents. |
