Alpha-adrenergic and 5-HT2-serotonergic effects of some beta-phenylethylamines on isolated rat thoracic aorta.

1. 2C-H [2-(2,5-dimethoxyphenyl)ethylamine] (pD2 = 6.74), TMPEA [2,(2,4,5-trimethoxyphenyl)ethylamine] (pD2 = 5.83), 2C-D [2-(2,5-dimethoxy-4-methylphenyl)ethylamine] (pD2 = 5.06), homoveratrylamine [DMPEA, 2-(4,5-dimethoxyphenyl)ethylamine] (pD2 = 4.46) and homopiperonylamine [MDPEA, 2-(3,4-methylenedioxyphenyl)ethylamine] (pD2 = 4.19), elicit concentration-dependent contraction of the isolated rat thoracic aorta. 2. At 9.9 x 10(-6) M, 2C-N [2-(2,5-dimethoxy-4-nitrophenyl)ethylamine] behaves as a competitive antagonist to serotonin in this preparation. 3. Considering previous results with the structurally related 2C-B [2-(4-bromo-2,5-dimethoxyphenyl)ethylamine], weak or partial agonistic activity or antagonism of aortic contraction appears to be related to psychedelic properties reported in humans for phenylethylamines.