Analysis of the anticholinergic and musculotropic effects of desmethylimipramine on the rabbit urinary bladder.

The anticholinergic and musculotropic relaxant properties of desmethylimipramine (DMI) on smooth muscle were investigated utilizing cholinergic radioligand receptor binding and in-vitro muscle bath techniques. Receptor binding studies revealed the direct antimuscarinic potency of DMI to be 1/480th that of atropine. Muscle bath studies characterized discrete antimuscarinic and musculotropic actions. An initial, competitive antimuscarinic action could be separated from a delayed onset, noncompetitive musculotropic action by altering the time between the addition of DMI and the addition of bethanechol to the smooth muscle bath. [ABSTRACT FROM AUTHOR]