Chronic lumbar catheterization of the spinal subarachnoid space in mice

A simple method for chronic intrathecal (i.t.) catheterization of the lumbar subarachnoid space in mice is described. The procedure does not require major surgery and does not produce neurological deficits. The intrathecal catheter stayed in place and was functional for at least 10 days. Morphological studies revealed no histological damage in the spinal cord after catheter implantation. The effects of acute and chronic intrathecal morphine were studied and compared between the current method and that of acute lumbar puncture. Morphine produced similar antinociceptive effect when administered acutely. All mice with catheters responded reliably to daily morphine injection up to 5 days whereas it was difficult to inject drugs repeatedly with lumbar puncture. It is concluded that this novel method of chronic lumbar catheterization in mice has advantages over the existing lumbar puncture technique for intrathecal delivery of drugs upon repeated administration. This method may be particularly useful in studies of genetically modified mice where the number of mice available is often limited.