ACTIONS OF SYMPATHOMIMETIC DRUGS ON THE SMOOTH MUSCLE AT THE JUNCTION OF THE BILE DUCT AND DUODENUM STUDIED IN SITU.

The actions of adrenaline, noradrenaline, phenylephrine and isoprenaline have been examined on flow through the terminal bile duct and on the tone of the duodenum in the vicinity of the terminal bile duct. These drugs were injected intravenously, or intra-arterially into the blood supply of the junction of the bile duct and duodenum. The effects of the antagonistic drugs, dibenamine and dichloroisoprenaline, were also tested. Isoprenaline always relaxed the duodenum and increased the flow through the bile duct. Adrenaline, noradrenaline and phenylephrine relaxed the duodenum, but had variable effects on the flow through the bile duct. It is concluded that adrenaline acts directly on the smooth muscle of the bile duct to contract it, but the influence of the neighbouring duodenal muscle may nevertheless result in an increase in flow through the duct.