Background: Neuropathic pain (NP) is one of the most challenging clinical problems to treat spinal cord injury (SCI). Rolipram is a specific PDE4 inhibitor that has been shown to reduce hyperalgesia in a rat chronic arthritic model. Purpose: To study the effect of Delayed rolipram on thermal hyperalgesia following spinal cord injury. Methods: Spinal cord contusion injury (SCI) were given to male SD rats. Thermal Hyperalgesia was assessed. Rolipram (0.15 mg/day) or vehicle (DMSO) was administered via a subcutaneously implanted micro-osmotic pump for 14 days. Hind-limb withdrawal (WLT) TH testing was performed. Results: The administration of continuous subcutaneous rolipram in rats starting at the time of delayed TH development significantly decreased the manifestation of TH as measured by hindlimb withdrawal latency time (WLT). The administration of continuous subcutaneous DMSO vehicle had no significant effect on hindlimb WLT for animals demonstrating TH and in rats demonstrating no evidence of TH, neither rolipram nor DMSO provided significant changes in WLT. Conclusion: Neuropathic pain is a complex process, therefore the timing, route, and animal model employed must all be considered when comparing results from different laboratories.

doi: 10.5214/ans.0972.7531.2008.150201 

Competing interests: None.  Source of Funding: None

Received Date: 21 Feb 2008     Revised Date: 30 March 2008     Accepted Date: 10 April 2007