The in vitro monoamine oxidase inhibitory (MAOI) activities of 11 heteroarylisopropylamines vis-a-vis MAO-A and MAO-B were described and interpreted in terms of possible interactions with the enzyme active site. Molecular dynamics simulations allowed a comparison between the most active MAO-A inhibitor of the series, the 1-(2-benzofuryl)-2-aminopropane, and the specific, analogous MAO-A substrate serotonin. (c) 2005 Elsevier Ltd. All rights reserved.