Indomethacin blocks central nociceptive effects of PGF2 alpha.

Intrathecal administration of PGE2 and PGF2 alpha and intradermal administration of PGE2 but not PGF2 alpha, in low doses, produce hyperalgesia as measured by the Randall-Selitto paw-withdrawal test. Indomethacin (2 mg/kg, i.p.) prevented intrathecal PGF2 alpha, but not PGE2-induced hyperalgesia. We propose that the central nociceptive effects of PGF2 alpha are mediated, indirectly, by effecting the cyclo-oxygenation of arachidonic acid in the central nervous system.