Modulation of neuropathic pain in rats by intrathecally injected serotonergic agonists

The involvement of spinal cord serotonergic influences in the development of autotomy, a proposed behavioural model of denervation pain, was studied in rats subjected to sciatic and saphenous nerve transection 5 min after intrathecal injection of 100 or 200 mu g of several serotonergic receptor subtype agonists. Injection of 8-OH-DPAT, m-CPP, 2-m-5-HT and a low dose of 5-HT, significantly shifted one or more of the parameters describing autotomy to less intense behaviour. In contrast, the injection of CGS-12066B and DOI intensified autotomy. These results suggest both a modulatory role for spinal cord serotonin in the events occurring shortly after neurectomy and new therapeutic approaches for the prevention of certain pain syndromes, such as phantom limb pain.