A novel bile duct cannulation method with tail cuff exteriorization allowing continuous intravenous infusion and enterohepatic recirculation in the unrestrained rat

A variety of bile duct cannulation methods have been used in the study of b iliary excretion in the rat. We now report the validation and use of one su ch method. In this method, the common bile duct and duodenum were cannulate d, the free ends of the cannulae tunnelled through the abdominal wall, pass ed through a trochar and exteriorized at the ventral aspect of the tail. A purpose-designed stainless steel tail cuff was then attached, to protect th e cannulae from the rat. The cannulae were passed through the top of a meta bolism cage and attached to a dual swivel that allows the rat freedom of mo vement within the metabolism cage. Where necessary an additional cannula co uld be placed in the femoral vein to allow infusion of test material or blo od sampling. The results demonstrate that the method is robust and that its use allows a reliable correlation between surgically prepared and intact a nimals, as physiological parameters are allowed to return to normal prior t o inclusion of the animals in the study. The technique allows the animals a great deal of freedom and, as such, is considered to minimize stress assoc iated with the procedure. This fact is reflected in the reliability and rep roducibility of the data obtained over the wide range of studies that have been conducted using this method. This method has been in use for over 4 ye ars at Inveresk and this paper describes the authors' experience with the m ethod to date.