A double-lumen intrathecal catheter for studies of modulation of spinal opiate tolerance.

Studies of spinal opioid tolerance frequently employ a spinal infusion model in which a single-lumen intrathecal (IT) catheter is connected to an osmotic mini pump. We have modified this model by developing a double-lumen catheter system that permits continuous delivery of the toleragen to the IT space and allows for examination of the effects of concurrent IT drug administration without interruption of the ongoing infusion. The catheter is constructed of two pieces of PE10 tubing fused to the lumens of a dual-lumen catheter (8 cm) with one PE10 tube used as an infusion line connected to an osmotic pump and the other for injection. The catheter is inserted through the cisterna magna. Most implanted rats (66 out of 73) showed full recovery of motor and sensory function without detectable neurological deficit. The profile of the tolerance development and the response to drug manipulation using the double-lumen catheter are similar to previous findings in the spinal infusion model which used a single-lumen catheter. Most importantly, we demonstrate that concurrent probe drug testing and/or concurrent drug treatment can be achieved without interruption of spinal infusion of morphine. Using the double-lumen catheter model expands the range of possibility for studies of spinal opiate tolerance and spinal drug delivery.