1. The muscle of bile ducts does not connect with duodenal muscle and ganglion cells are observed in the submucosa and muscle layers. There is no special sphincter muscle in the orifice of the duct.
2. The bile is transproted by peristalses from hepatic side to the duodenum in vivo.
3. In the isolated bile duct (hepato-duodenal duct), raising the intraluminal pressure induced rhythmic contraction or increased spontaneous contraction.
4. Adernaline, noradrenaline and phenylephrine as well as acetylcholine increased the contraction, while isoprenaline inhibited the spontaneous contraction in number. After treatment with pindroll, adrenaline strengthened the contraction, while after treatment with phenoxybenzamine the excitatory effect responsbile to adrenaline was abolished.
5. The excitatory effect of nicotine was abolished after tetrodotoxin, but the excitatory effect induced by raising intraluminal pressure was not abolished with tetrodotoxin. However, after treatment of hexamethonium bromide, nicotine or atropine, the excitatory effect of raising intraluminal pressure was slightly reduced. It is supposed that the contraction induced by raising intraluminal pressure after treat-ment of these agents is myogenic in origin.