Lambrecht G, Feifel R, Moser U, Aasen A J, Waelbroeck M, Christophe J, Mutschler E
Department of Pharmacology, University of Frankfurt, Federal Republic of Germany.
Eur J Pharmacol. 1988 Oct 11;155(1-2):167-70. doi: 10.1016/0014-2999(88)90417-7.
High stereoselectivity was observed for the enantiomers of trihexyphenidyl and trihexyphenidyl methiodide at muscarinic M1-receptors in field-stimulated rabbit vas deferens and at M2 alpha- and M2 beta-receptors in guinea-pig atrium and ileum, respectively. Considerably higher affinities (up to 1700-fold) were found for the (R)-(-)-enantiomers. The stereochemical demands made by the muscarinic receptor subtypes were most stringent at the M1-receptors. The (R)-(-)-enantiomers were found to be potent M1-selective antagonists (pA2 = 10.1/10.6). They showed a 91- and 45-fold selectivity for M1- over M2 alpha-receptors, respectively.
