Effects of autonomic agonists on in vivo female canine urethral motility

The response of the urethra to intra-arterially administered autonomic agonists was studied in vivo by measuring the motility and pressure changes in female dogs. Phenylephrine produced shortening along the transverse axis with an increase in urethral pressure in a dose-dependent manner. Isoproterenol produced lengthening along the transverse axis with a decrease in urethral pressure. Both acetylcholine and dimethylphenylpiperazinium did not produce consistent patterns in urethral response. It seems that adrenergic drugs act predominantly on the circular muscle layer and cholinergic drugs act equally on both the circular and longitudinal muscle layers.