ALPHA-ADRENERGIC AND 5-HT2-SEROTONERGIC EFFECTS OF SOME BETA-PHENYLETHYLAMINES ON ISOLATED RAT THORACIC AORTA

1. 2C-H [2-(2,5-dimethoxyphenyl)ethylamine] (pD(2), = 6.74), TMPEA [2- (2,4,5-trimethoxyphenyl)ethylamine] (pD(2) = 5.83), 2C-D [2-(2,5-dimet hoxy-4-methylphenyl)ethylamine] (pD(2) = 5.06), homoveratrylamine [DMP EA, 2-(4,5-dimethoxyphenyl)ethylamine] (pD(2) = 4.46) and homopiperony lamine [MDPEA, 2-(3,4-methylenedioxyphenyl)ethylamine] (pD(2) = 4.19), elicit concentration-dependent contraction of the isolated rat thorac ic aorta. 2. At 9.9 x 10(-6) M, 2C-N [2-(2,5-dimethoxy-4-nitrophenyl)e thylamine] behaves as a competitive antagonist to serotonin in this pr eparation. 3. Considering previous results with the structurally relat ed 2C-B [2-(4-bromo-2,5-dimethoxyphenyl)ethylamine] , weak or partial agonistic activity or antagonism of aortic contraction appears to be r elated to psychedelic properties reported in humans for phenylethylami nes.