Potential modes of interaction of 9-aminomethyl-9,10-dihydroanthracene (AMDA) derivatives with the 5-HT2A receptor: A ligand structure-affinity relationship, receptor mutagenesis and receptor modeling investigation

Abstract

The effects of 3-position substitution of 9-aminomethyl-9,10-dihydroanthracene (AMDA) on 5-HT2A receptor affinity were determined and compared to a parallel series of DOB-like 1-(2,5-dimethoxyphenyl)-2-aminopropanes substituted at the 4-position. The results were interpreted within the context of 5-HT2A receptor models that suggest that members of the DOB-like series can bind to the receptor in two distinct modes that correlate with the compounds’ functional activity. Automated ligand docking and molecular dynamics suggest that all of the AMDA derivatives, the parent of which is a 5-HT2A antagonist, bind in a fashion analogous to that for the sterically demanding antagonist DOB-like compounds. The failure of the F3406.52L mutation to adversely affect the affinity of AMDA and the 3-bromo derivative is consistent with the proposed modes of orientation. Evaluation of ligand?receptor complex models suggest that a valine/threonine exchange between the 5-HT2A and D2 receptors may be the origin of selectivity for AMDA and two substituted derivatives.