Title
Role of the excitability brake potassium current I<inf>KD</inf> in cold allodynia induced by chronic peripheral nerve injury
Date Issued
22 March 2017
Access level
open access
Resource Type
journal article
Author(s)
González A.
Ugarte G.
Restrepo C.
Herrera G.
Piña R.
Gómez-Sánchez J.A.
Pertusa M.
Orio P.
Madrid R.
Publisher(s)
Society for Neuroscience
Abstract
Cold allodynia is a common symptom of neuropathic and inflammatory pain following peripheral nerve injury. The mechanisms under-lying this disabling sensory alteration are not entirely understood. In primary somatosensory neurons, cold sensitivity is mainly deter-mined by a functional counterbalance between cold-activated TRPM8 channels and Shaker-like Kv1.1-1.2 channels underlying the excitability brake current IKD. Here we studied the role of IKD in damage-triggered painful hypersensitivity to innocuous cold. We found that cold allodynia induced by chronic constriction injury (CCI) of the sciatic nerve in mice, was related to both an increase in the proportion of cold-sensitive neurons (CSNs) in DRGs contributing to the sciatic nerve, and a decrease in their cold temperature threshold. IKD density was reduced in high-threshold CSNs from CCI mice compared with sham animals, with no differences in cold-induced TRPM8-dependent current density. The electrophysiological properties and neurochemical profile of CSNs revealed an increase of nociceptive-like phenotype among neurons from CCI animals compared with sham mice. These results were validated using a mathe-matical model of CSNs, including IKD and TRPM8, showing that a reduction in IKD current density shifts the thermal threshold to higher temperatures and that the reduction of this current induces cold sensitivity in former cold-insensitive neurons expressing low levels of TRPM8-like current. Together, our results suggest that cold allodynia is largely due to a functional downregulation of IKD in both high-threshold CSNs and in a subpopulation of polymodal nociceptors expressing TRPM8, providing a general molecular and neural mechanism for this sensory alteration.
Start page
3109
End page
3126
Volume
37
Issue
12
Language
English
OCDE Knowledge area
Neurología clínica Farmacología, Farmacia
Scopus EID
2-s2.0-85016036575
PubMed ID
Source
Journal of Neuroscience
ISSN of the container
02706474
Sponsor(s)
This work was supported by FONDECYT Grants 1161733 and 1131064 to R.M., 1130862 to P.O., 11130144 to M.P., and 3150431 to A.G., CONICYT Anillo Grant ACT-1113 to R.M., P.O., M.P., and G.U., and the Advanced Center for Electrical and Electronic Engineering CONICYT FB0008 to P.O. R.M. thanks Pfizer Inc. (WI177114) and VRIDEIUSACH. G.H. holds a CONICYT PhD fellowship. The Centro Interdisciplinario de Neurociencia de Valparaíso is a Millennium Science Institute funded by the Ministry of Economy, Chile. The funders had no role in study conception, design, data collection, and interpretation or in the decision to submit the manuscript for publication. We thank Drs. F. Viana and C. Belmonte for comments on the manuscript; and J. Salas, M. Campos, and R. Pino for excellent technical assistance.
Sources of information: Directorio de Producción Científica Scopus