Simple and reliable method for serial sampling of blood from rats

A technique for serial sampling of whole blood, plasma, or serum from unanesthetized, unrestrained rats is described. This technique is sufficiently rapid, reliable, and independent of the need for elaborate preparation, specialized equipment, or practiced skills to appeal to a wide range of experimental and teaching situations requiring multiple sampling from many animals. A simple surgical procedure implants a one-piece jugular cannula cut from a commercial coil of silicone polymer tubing. Multiple blood samples are almost immediately available for 5 weeks or more. Plasma or serum samples are readily obtainable from each blood sample without transfer from the syringe in which it is collected. Intravenous injection through the cannula does not prejudice later sampling protocol.