Intermittent lumbar puncture in rats: a novel method for the experimental study of opioid tolerance.

Spinal subarachnoid opioid administration in rats has been a very important method for studying the pharmacological effects of opioids, including analgesia and tolerance. Intrathecal catheterization, either through the cervical or lumbar approach, has been the predominant method used to deliver opioids spinally. However, these methods have potential undesirable complications. To help mitigate these problems, we have developed a method of intermittent lumbar puncture in rats to study the effects of chronic spinal opioid administration. This method avoids catheter-associated morbidity. We demonstrate that this method can be readily used to induce spinal opioid tolerance without causing morbidity. Intermittent lumbar puncture should prove to be a useful technique for investigating mechanisms of spinal opioid analgesia and opioid tolerance development.