A simplified method for chronic portal vein cannulation in the rat.

A simple technique is described for chronic cannulation and repeated blood sampling from the portal vein of the conscious undisturbed rat. The method employs a straight cannula and allows precise location of the tip. Blood flow in the portal vein is not obstructed. The present technique was used in combination with chronic cannulation of the superior vena cava. Simultaneous blood sampling from the two cannulas was successfully carried out at fifteen minute intervals over six hour periods. The system and the sampling were well tolerated by the rats.