In vitro action of digitalis on guinea pig detrusor and urethra

An in vitro investigation of the action of ouabain on the guinea pig bladder and urethra is presented Detrusor strips responded with an increase in baseline tension and in the amplitude and frequency of contractions. The response of the detrusor to ouabain was not significantly altered by phentolamine, propranolol, or hexamethonium. The response of the detrusor to ouabain was significantly reduced, but not abolished, by atropine suggesting that ouabain acts mainly by stimulating cholinergic receptors in the detrusor although it may also have some direct action on the detrusor smooth musculature. The action of ouabain on the guinea pig urethra was inconsistent. The most common response was a slight decrease in urethral tension.