INHIBITION OF NEUROGENIC INFLAMMATION IN THE MENINGES BY A NONPEPTIDENK1 RECEPTOR ANTAGONIST, RP-67580

RP 67580, a non-peptide NK1 receptor antagonist, inhibited in a stereo selective and dose-depen ent manner plasma extravasation caused in the dura mater by intravenous injection of capsaicin in guinea-pigs and o f exogenous substance P in rats (ED50 = 35 and 2.5 mug/kg i.v., respec tively). In the two species, RP 67580 appeared to be more effective in the dura mater than in the peripheral organs. These results indicate that selective NK1 receptor antagonists could be potentially effective for the treatment of migraine headache.