In vitro effect of amezinium on the rabbit urinary bladder: muscle strip and whole bladder evaluation

Dose-response studies for norepinephrine and amezinium were obtained for isolated muscle strips and in vitro whole bladder preparations to investigate the effect of amezinium on the bladder. Specimens (strips from the bladder base and body, and the whole bladder) were obtained from mature female rabbits. By the muscle strip study, amezinium showed a weak contractile effect (up to 40% of spontaneous contraction) on strips from the bladder base. Muscle strips from the bladder body presented no response to amezinium. In the whole bladder preparation, administration of norepinephrine showed an increase in intravesical pressure in 4 out of 7 rabbits, whereas administration of amezinium had negligible effect on intravesical pressure. Administration of amezinium showed no influence on strips from the bladder body and the whole bladder preparation. Direct contractile response in muscle strips from the bladder base by amezinium appeared to be a favourable effect considering urinary storage.