COMPARISON OF THE EFFECTS OF VARIOUS SPASMOLYTIC DRUGS ON ISOLATED HUMAN AND PORCINE DETRUSOR SMOOTH-MUSCLE

The spasmolytic activity of flavoxate (CAS 15301-69-6), anticholinergi c agents oxybutynin (CAS 5633-20-5), and trospium chloride (CAS 10405- 02-4), drugs commonly utilized in the therapy of hyperactive bladder, and phosphodiesterase (PDE) inhibitors papaverine (CAS 58-74-2) and vi npocetine (CAS 42971-09-5) on muscarinic contractions of detrusor smoo th muscle strips isolated from human and porcine urinary bladder was s tudied in vitro using the organ bath technique. Trospium chloride was most effective in relaxing contractions elicited by muscarinic stimula tion, while flavoxate was significantly less effective than all other drugs tested. The relaxing potency of oxybutynin was greater than thos e of PDE-inhibitors papaverine and vinpocetine but 3,000 fold less sig nificant than those of trospium chloride. The effects of the individua l drugs on muscarinic tension of both human and porcine detrusor muscl e strips were nearly equal. The present results suggest that the pig m ight be an appropriate animal model for the study of effects of spasmo lytic substances on the contractility of urinary bladder smooth muscle in vitro.