Purpose: Pregabalin exhibits potent anticonvulsant, analgesic, and anxiolytic activity in animal models. However, few studies have evaluated pregabalin's potential peripheral effects on neuropathic pain. The aim of this study was to evaluate the peripheral analgesic effects of pregabalin in a rat model of neuropathic pain.
Methods: Male Sprague-Dawley rats were prepared by ligating the left L5 and L6 spinal nerves to produce neuropathic pain. Sixty rats with neuropathic pain were randomly assigned to six groups. Normal saline (control) and pregabalin (10, 20, 30, and 50 mg.kg(-1)) were administered to the plantar surface of the affected left hind paw. Pregabalin (50 mg.kg(-1)) was administered into the unaffected contralateral paw in order to determine its systemic effect. Responses to mechanical, cold, and heat stimulation were recorded at 15, 30, 60, 90, 120, 150, and 180 min after drug administration. Rotarod performance was measured to detect drug-induced side effects, including sedation and reduced motor coordination.
Results: Saline injected into the affected paw and a pregabalin dose of 50 mg.kg(-1) injected into the contralateral paw showed no differences for mechanical, cold, and heat allodynia. Administration of pregabalin to the affected left hind paw in the dose range of 10-50 mg.kg(-1) resulted in a dose-dependent increase in thresholds to mechanical, cold, and heat stimulation.
Conclusion: Peripherally administered pregabalin attenuates mechanical, cold, and heat allodynia in a rat model of neuropathic pain.