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RAPID REPORT: An in vivo tethered toxin approach for the cell‐autonomous inactivation of voltage‐gated sodium channel currents in nociceptors
Author(s) -
Stürzebecher Annika S.,
Hu Jing,
Smith Ewan St John,
Frahm Silke,
SantosTorres Julio,
Kampfrath Branka,
Auer Sebastian,
Lewin Gary R.,
IbañezTallon Inés
Publication year - 2010
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2010.187112
Subject(s) - sodium channel , nociceptor , in vivo , biophysics , toxin , chemistry , channel (broadcasting) , sodium , microbiology and biotechnology , computer science , biochemistry , biology , nociception , computer network , receptor , organic chemistry
Understanding information flow in sensory pathways requires cell‐selective approaches to manipulate the activity of defined neurones. Primary afferent nociceptors, which detect painful stimuli, are enriched in specific voltage‐gated sodium channel (VGSC) subtypes. Toxins derived from venomous animals can be used to dissect the contributions of particular ion currents to cell physiology. Here we have used a transgenic approach to target a membrane‐tethered isoform of the conotoxin MrVIa (t‐MrVIa) only to nociceptive neurones in mice. T‐MrVIa transgenic mice show a 44 ± 7% reduction of tetrodotoxin‐resistant (TTX‐R) VGSC current densities. This inhibition is permanent, reversible and does not result in functional upregulation of TTX‐sensitive (TTX‐S) VGSCs, voltage‐gated calcium channels (VGCCs) or transient receptor potential (TRP) channels present in nociceptive neurones. As a consequence of the reduction of TTX‐R VGSC currents, t‐MrVIa transgenic mice display decreased inflammatory mechanical hypersensitivity, cold pain insensitivity and reduced firing of cutaneous C‐fibres sensitive to noxious cold temperatures. These data validate the use of genetically encoded t‐toxins as a powerful tool to manipulate VGSCs in specific cell types within the mammalian nervous system. This novel genetic methodology can be used for circuit mapping and has the key advantage that it enables the dissection of the contribution of specific ionic currents to neuronal function and to behaviour.