Contribution of a helix 5 locus to selectivity of hallucinogenic and nonhallucinogenic ligands for the human 5-hydroxytryptamine2A and 5-hydroxytryptamine2C receptors: direct and indirect effects on ligand affinity mediated by the same locus. - Almaula N; Ebersole BJ; Ballesteros JA; Weinstein H; Sealfon SC. (1996)