Electrophysiological properties of spinal wide dynamic range neurons in neuropathic pain rats following spinal nerve ligation

Abstract

Objective: The present study aimed to investigate the electrophysiological properties of wide dynamic range (WDR) neurons in spinal dorsal horn of rats with neuropathic pain induced by lumber 5 (L5) spinal nerve ligation (SNL) in a large size of samples. Methods: Adult Sprague-Dawley rats were divided into normal and SNL groups. Electrophysiological technique was used to record the characteristics of WDR neurons in the spinal dorsal horn. Results: Compared with the WDR neurons in normal rats, the WDR neurons in SNL rats showed an increase in excitability, manifested by an enlargement of the receptive field size, an increase in the proportion of neurons that exhibited spontaneous activities, decreases in the Cresponse threshold and latency, and an increase in the C-response duration. In addition, the numbers of Aβ- and C-fiberevoked discharges were smaller in SNL rats than in normal rats. Conclusion: The excitability of spinal WDR neurons increased in rats with neuropathic pain induced by L5 SNL. The increase in excitability of WDR neurons may contribute to the development of neuropathic pain. © 2011 Shanghai Institutes for Biological Sciences, CAS and Springer-Verlag.