Binding site of loperamide: automated docking of loperamide in human mu- and delta-opioid receptors.

Loperamide is a piperidine analogue, acting as agonist on peripheral opioid receptors, exhibiting affinity and selectivity for the cloned mu human opioid receptor compared with the delta human opioid receptor. Automatic docking studies of loperamide, using AutoDock, on human mu- and delta-opioid receptors is described. Whilst no meaningful difference was detected concerning the docking of the arylpiperidine moiety, mu/delta selectivity could be explained as a different accommodation of the two phenyl groups in two lipophylic pockets of receptors.