The depletion of substance P by diclofenac in the mouse.

Diclofenac in hyaluronan is analgesic and angiostatic. The depletion of substance P may be a common mechanism. Mice received diclofenac, diclofenac in hyaluronan, or saline i.v. for 5 days and snout substance P assessed: saline 2.80 +/- 0.23; 0.5 mg/kg diclofenac 2.03 +/- 0.20 (P < 0.05); diclofenac in hyaluronan 1.88 +/- 0.21 (P < 0.02); capsaicin 1.45 +/- 0.26 fmol/mg tissue (P < 0.005). Substance P recovered by 5 days (diclofenac in hyaluronan, capsaicin) and 24 h (diclofenac). Diclofenac may deplete substance P in analgesia, and hyaluronan prolong the depletion.