THE ROLE OF SEROTONIN BRAIN RECEPTORS IN THE ANALGESIC EFFECT OF PHENAZONE

The effects of treatment with para-chloro-phenyl-alanine (PCPA) (100 mg/kg i.p. for 4 days) were studied on the hot-plate test and on brain 5-HT binding in phenazone treated rats. Phenazone per se induces analgesia in the hot-plate test and decreases the number of cortical and pontine 5-HT binding sites. A pre-treatment with PCPA prevents both the analgesic effect and the reduction of 5-HT binding sites caused by phenazone. These data suggest that the brain serotonin system may play a role in phenazone-induced antinociception.