[The spasmolytic activity of propiverine and some of its structural analogs]

The spasmolytic activity of propiverine and its corresponding methyl ether analogue was investigated in the isolated ileum and urinary bladder of the rat. It could be demonstrated that the antispasmodic properties of propiverine were, in contrast to its methyl ether analogue, not only based on a blockade of muscarinic receptors but were also a consequence of nonspecific papaverine-like effects. Investigations with three putative metabolites showed that the alcohol derivative O-desalkylpropiverine was about two orders of magnitude more potent than propiverine itself in blocking spasmogenic effects of the agonist arecaidine propargyl ester. In contrast no spasmolytic effect could be observed after application of the corresponding carboxylic acids (benzilic acid propyl ether; benzilic acid 2-hydroxypropyl-ether.