piperidines and oxyphencyclimine

We investigated the binding properties of the (R)- and (S)-enantiomers of the muscarinic antagonists trihexyphenidyl, procyclidine, hexahydro-difenidol, p-fluoro-hexahydro-difenidol, hexbutinol, p-fluoro-hexbutinol, and their corresponding methiodides at muscarinic M1, M2, M3 and M4 receptor subtypes. In addition, binding properties of the (R)- and (S)-enantiomers of oxyphencyclimine were studied. The (R)- enantiomers (eutomers) of all the compounds had a greater affinity than the (S)-isomers for the four muscarinic receptor subtypes. The binding patterns of the (R)- and (S)-enantiomers were generally different. We did not observe any general correlation between the potency of the high-affinity enantiomer and the affinity ratio (eudismic ratio) of the two enantiomers. The results are discussed in terms of a 'four subsites' binding model.

Topics: Alkynes; Animals; Corpus Striatum; Heart; Humans; In Vitro Techniques; Male; N-Methylscopolamine; Neuroblastoma; Pancreas; Parasympatholytics; Piperidines; Procyclidine; Pyrimidines; Rats; Rats, Inbred Strains; Receptors, Muscarinic; Scopolamine Derivatives; Stereoisomerism; Tritium