I - Prostaglandin hyperalgesia, a cAMP/Ca2+ dependent process.
Prostaglandins stimulate cAMP increase in several biological systems including CNS. The possible participation of a cAMP/Ca2+ related mechanism in prostaglandin induced hyperalgesia in the rat paw, as measured by a modification of the Randall-Selitto method was investigated. A serie of agents was administered in the paw in an attempt to change either Ca2+ or cyclic AMP concentration at the nociceptive terminations. PGE2, dibutyryl cyclic AMP, isoprenaline, noradrenaline, adrenaline, Ca2+ionophore (A23187), BaCl2 caused a dose dependent hyperalgesia. The hyperalgesic effect of these substances was enhanced by methyl-xanthines. Cyclic GMP as well as agents which interfere with Ca2+ influx (verapamil and lanthanum) were local analgesics in normal and hyperalgesic paws.
D000700:Analgesics; D000818:Animals; D001464:Barium / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002395:Catecholamines / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004357:Drug Synergism; D006930:Hyperalgesia / Q000139:chemically induced*; D006941:Hyperesthesia / Q000139:chemically induced*; D009619:Nociceptors / Q000187:drug effects*; D011458:Prostaglandins E / Q000494:pharmacology*; D051381:Rats; D014970:Xanthines / Q000494:pharmacology
D000700:Analgesics; D002395:Catecholamines; D011458:Prostaglandins E; D014970:Xanthines; D001464:Barium; D000001:Calcimycin; D003994:Bucladesine; D000242:Cyclic AMP; D002118:Calcium