(S)-UH-301 ANTAGONIZES (R)-8-OH-DPAT-INDUCED CARDIOVASCULAR EFFECTS IN THE RAT

The 5-HT1A-receptor antagonist (S)-UH-301 (S)-5-fluoro-8-hydroxy-2-(dipropylamino)tetralin) completely antagonized the hypotension and bradycardia induced by (R) = 8-OH DPAT ((R)-8-hydroxy-2-(dipropylamino)tetralin) in conscious rats. (S)-UH-301 alone induced a weak hypertension, which might be due to its 5-HT1A-receptor antagonistic properties. (R)-UH-301 induced effects similar to those of (R)-8-OH DPAT, i.e., a short initial phase of hypertension followed by a long-lasting hypotension and bradycardia. Thus, (R)-UH-301 behaves as a 5-HT1A-receptor agonist and (S)-UH-301 as a 5-HT1A-receptor antagonist, abolishing the effects induced by (R)-8-OH DPAT.