Long term catheterization of the lumbar epidural space in rats

This note describes a simple technique for the administration of drug solutions into the lumbar epidural space of the unanesthetized and freely moving rat. A poly-ethylene (PE-10) catheter is inserted into the epidural space through a hole in the third lumbar vertebra, and subcutaneously tunneled towards the neck region. The implantation procedure is well-tolerated, and repeated saline injections over a prolonged period of time were found not to exert any deleterious effect on the animals' apparent health or gross behavior. The viability of the technique is demonstrated in an experiment on the effect of injection volume on the analgesic action of epidurally administered fentanyl.