EFFECT OF SPINAL CYCLOOXYGENASE INHIBITORS IN RAT USING THE FORMALIN TEST AND IN-VITRO PROSTAGLANDIN E-2 RELEASE

Spinally delivery of the non-specific cyclooxygenase inhibitor, S(+)-i buprofen, reduces the second phase of the formalin test and the evoked release of prostaglandin E-2 (prostaglandin E-2) from rat spinal cord in vitro. Using two selective cyclooxygenase-2 inhibitors, SC58125 yl ]-3-tri-fluoromethyl-5-(4-fluorophenyl)pyrazole) and SC-236 -(4-chloro phenyl)-3-(trifluoromethyl)-1H-pyrazol-1 -yl]benzenesulfonamide), we o bserved that neither agent at the highest dose/concentration employed altered the second phase of the formalin test after intrathecal delive ry or K+-evoked prostaglandin E-2 release from spinal cord in vitro, a lthough ibuprofen was effective in both models. These observations sug gest that cyclooxygenase-2 may not be associated with spinal prostanoi d synthesis acutely or with facilitated nociception which occurs withi n the limited time frame of the formalin test. (C) 1997 Elsevier Scien ce B.V.