Displacement of serotonin from binding sites in rat cortex: the effects of biogenic "trace" amines.
The concentrations for 50 percent inhibition of binding (IC50's) to specific in vitro serotonin binding sites (5-HT1 and 5-HT2) of rat cerebral cortex were determined for the trace amines 2-phenylethylamine, m- and p-tyramine, tryptamine, and (+)- and (-)- alpha-methyltryptamine. Tryptamine gave an IC50 of 66.7 +/- 4.8 nM (n = 7) at the 5-HT1 site and an IC50 of 3.85 +/- 0.16 microM (n = 7) for the 5-HT2 binding site. The IC50 values for all the other compounds were in the micromolar range and were different at the two binding sites except for p-tyramine (IC50, 5-HT1 = IC50, 5-HT2 = 17 microM. The trace amines may have different functional roles as evidenced by their different degrees of displacement of serotonin at 5-HT1 and 5-HT2 binding sites in the brain.
D000818:Animals; D005625:Frontal Lobe / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D010627:Phenethylamines / Q000494:pharmacology; D051381:Rats; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D013237:Stereoisomerism; D014363:Tryptamines / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology
D010627:Phenethylamines; D011985:Receptors, Serotonin; D014363:Tryptamines; C029261:phenethylamine; D012701:Serotonin; C030820:tryptamine; C015293:indopan; C028169:3-tyramine; D014439:Tyramine