Potassium Chloride Cotransporter 2 Inhibits Neuropathic Pain and Future Development of Neurodegeneration.

Abstract

Persistent neuropathic pain (NP) causes future development of neurodegenerative diseases, e.g., Alzheimer' disease, and thus needs to be optimally treated. Surgically-induced neuropathic pain (SNPP) is a persistent pain that occurs in nearly half of the individuals after common operations. Here, we showed that specific activation of 5-hydroxytryptamine (5-HT) type 2A receptors by systemic administration of TCB-2 [(4-bromo-3,6-dimethoxybenzocyclobuten-1-yl) methylamine hydrobromide] improved the function of potassium chloride cotransporter 2 (KCC2), resulting in reduction in neuropathic pain after chronic constriction injury (CCI), a rat model that mimics SNPP. Moreover, TCB-2 administration attenuated both mechanical and thermal hyperalgesia, likely through augmentation of dorsal horn KCC2 levels, since this effect was abolished by intrathecal provision of dihydroindenyl oxy alkanoic acid (DIOA), which blocked the effects of KCC2. Furthermore, TCB-2-mediated re-activation of KCC2 likely reduces future development of neurodegeneration in rats. Together, our data support further studies on the possibility of using this strategy to reduce postoperative pain and future neurodegenerative disorders in clinic.