|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Medicine, Laval University, Quebec, Canada
2 Medicine, Laval University, Quebec, Canada; Quebec, Canada
3 Pathol/Anat/Cell Biol, Thomas Jefferson Univ, United States
* To whom correspondence should be addressed. E-mail: mohamed.chahine{at}phc.ulaval.ca.
Nociceptive neurons of the dorsal root ganglion (DRG) express a combination of rapidly gating TTX-sensitive and slowly gating TTX-resistant Na currents and the channels that produce these currents have been cloned. The Nav1.7 and Nav1.8 channels encode for the rapidly inactivating TTX-sensitive and slowly inactivating TTX-resistant Na currents respectively. Although the Nav1.7 channel expresses well in cultured mammalian cell lines, attempts to express the Nav1.8 channel using similar approaches has been met with limited success. The inability to heterologously express Nav1.8 has hampered detailed characterization of the biophysical properties and pharmacology of these channels. In this study we investigated the determinants of Nav1.8 expression in tsA201 cells, a transformed variant of HEK293 cells, using a combination of biochemistry, immunochemistry and electrophysiology. Our data indicate that the unusually low expression levels of Nav1.8 in tsA201 cells results from a trafficking defect that traps the channel protein in the endoplasmic reticulum. Incubating the cultured cells with the local anesthetic lidocaine dramatically enhanced the cell surface expression of functional Nav1.8 channels. The biophysical properties of the heterologously expressed Nav1.8 channel are similar but not identical to those of the TTX-resistant Na current of native DRG neurons, recorded under similar conditions. Our data indicates that the lidocaine acts as a molecular chaperone that promotes efficient trafficking and increased cell surface expression of Nav1.8 channels.
This article has been cited by other articles:
![]() |
L. M. Sharkey, X. Cheng, V. Drews, D. A. Buchner, J. M. Jones, M. J. Justice, S. G. Waxman, S. D. Dib-Hajj, and M. H. Meisler The ataxia3 Mutation in the N-Terminal Cytoplasmic Domain of Sodium Channel Nav1.6 Disrupts Intracellular Trafficking J. Neurosci., March 4, 2009; 29(9): 2733 - 2741. [Abstract] [Full Text] [PDF] |
||||
![]() |
C.-F. Wang, P. Gerner, B. Schmidt, Z. Z. Xu, C. Nau, S.-Y. Wang, R.-R. Ji, and G. K. Wang Use of Bulleyaconitine A as an Adjuvant for Prolonged Cutaneous Analgesia in the Rat Anesth. Analg., October 1, 2008; 107(4): 1397 - 1405. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. G. Schofield, H. L. Puhl 3rd, and S. R. Ikeda Properties of Wild-Type and Fluorescent Protein-Tagged Mouse Tetrodotoxin-Resistant Sodium Channel (NaV1.8) Heterologously Expressed in Rat Sympathetic Neurons J Neurophysiol, April 1, 2008; 99(4): 1917 - 1927. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |