Chiral muscarinic agonists possessing a 1,3-oxathiolane nucleus: enantio- and tissue-selectivity on isolated preparations of guinea-pig ileum and atria and of rat urinary bladder.

Racemate and corresponding enantiomers of muscarinic agonists carrying a 1,3-oxathiolane nucleus were studied on isolated preparations of guinea-pig ileum and atria and of rat urinary bladder. The efficacy of these agonists were determined according to the method of Furchgott and Bursztyn (1967) and enantio-selectivity and tissue-selectivity were investigated. The enantio-selectivities of the most potent compounds studied (expressed as the ratio of potencies or affinities of the enantiomers) vary significantly from tissue to tissue, supporting the view that M2 receptors are not homogeneous. In particular, the data all indicate that the ileal receptors are different to the atrial and bladder ones.