... in a lengthwise configuration. These anatomical studies show that canine ureteral smooth muscle is composed of spiral fibers in a mesh structure and that helical muscle strips which include a significant percentage of continuous bundles have a greater capacity to generate spontaneous contractions in vitro than do...

...Shinjiro Yano; Shoichi Ueda; Keiichi Ikegami The effects of some autonomic drugs on the isolated human minor calyceal strips were investigated quantitatively. Norepinephrine, epinephrine and phenylephrine dose dependently increased the basal tone and the frequency of spontaneous contractions...