Abstract
The effects of transmural electric stimulation, raising of intraluminal pressure, and application of some drugs on motility and intracellular potentials were studied in isolated chicken bile duct.
1. Peristaltic conduction velocity increased with increasing intraluminal pressure although the range in velocities recorded also increased.
2. Orthodromic and antidromic peristalses were induced by transmural electric stimulation of the hepatic and duodenal sides respectively. Localized contraction was induced by a single square pulse (0.2-1000 msec), but after treatment with tetrodotoxin, stimulation with a pulse below 0.5 msec in duration required a higher voltage to induce an equivalent contraction.
3. The membrane potential was -58.4±1.4 mV. When the bile duct contracted spontaneously, the membrane potential depolarized very slowly and a slow potential occured on which spike potentials of 30-40 mV were superimposed. Over shoot of the spike potential was sometimes observed. The same pattern of electrical activitywas obtained in the pacemaker area also.
4. Adrenaline prodcued a slightly hyperpolarization followed by depolarization. Isoprenaline resulted in hyperpolarization. After the application of atropine, the slow potential induced by transmural stimulation decreased in amplitude and duration and after-hyperpolarization occurred.
