Axotomy-Induced Expression of Calcium-Activated Chloride Current in Subpopulations of Mouse Dorsal Root Ganglion Neurons

Abstract

and Frédérique Scamps. Axotomy-induced expression of calciumactivated chloride current in subpopulations of mouse dorsal root ganglion neurons. J Neurophysiol 90: 3764 -3773, 2003. First published August 27, 2003 10.1152/jn.00449.2003. Whole cell patchclamp recordings of calcium-activated chloride current [I Cl(Ca) ] were made from adult sensory neurons of naive and axotomized mouse L 4 -L 6 lumbar dorsal root ganglia after 1 day of culture in vitro. A basal I Cl(Ca) was specifically expressed in a subset of naive mediumdiameter neurons (30 -40 m). Prior nerve injury, induced by sciatic nerve transection 5 days before experiments, increased both I Cl(Ca) amplitude and its expression in medium-diameter neurons. Moreover, nerve injury also induced I Cl(Ca) expression in a new subpopulation of neurons, the large-diameter neurons (40 -50 m). Small-diameter neurons (inferior to 30 m) never expressed I Cl(Ca) . Regulated I Cl(Ca) expression was strongly correlated with injury-induced regenerative growth of sensory neurons in vitro and nerve regeneration in vivo. Cell culture on a substrate not permissive for growth, D,L-polyornithine, prevented both elongation growth and I Cl(Ca) expression in axotomized neurons. Regenerative growth and the induction of I Cl(Ca) expression take place 2 days after injury, peak after 5 days of conditioning in vivo, slowly declining thereafter to control values. The selective expression of I Cl(Ca) within medium-and large-diameter neurons conditioned for rapid, efficient growth suggests that these channels play a specific role in postinjury behavior of sensory neuron subpopulations such as neuropathic pain and/or axonal regeneration.

Expression of three distinct families of calcium-activated chloride channel genes in the mouse dorsal root ganglion

“…DRGs. This time-point corresponds with the increased expression of ICl(Ca) in axotomized DRG neurons [1] . The results, shown in Fig.…”

“…These neurons express many types of ion channels, some of which have been shown to be responsible for the specific functional properties of particular neuronal sub-types responsible for defined sensory modalities. We recently reported the induction of a calcium-activated chloride current (I Cl(Ca) ) in a discrete population of sensory neurons of the dorsal root ganglion [1] . Axotomy of the sciatic nerve led to the massive induction of I Cl(Ca) in the vast majority of neurons of medium and large cell body diameter, generally thought to be low-threshold skin and muscle innervating neurons conveying touch and proprioceptive information.…”

Activation of Ca2+‐activated Cl− channel ANO1 by localized Ca2+ signals

“…Sensory neurons display robust CaCC currents (Mayer, 1985; Ward & Kenyon, 2000; Andre et al . 2003), which are most likely mediated by ANO1 channels (Liu et al . 2010; Cho et al .…”

“…However, subdivision of neurons into large (mostly mechano‐sensitive), medium and small (mostly nociceptive) neurons later revealed that while medium and large neurons express VGCC‐coupled CaCCs (Andre et al . 2003; Boudes et al . 2009; Boudes & Scamps, 2012), in small neurons such coupling is rarely seen (Andre et al .…”

“…2009; Boudes & Scamps, 2012), in small neurons such coupling is rarely seen (Andre et al . 2003; Liu et al . 2010; Boudes & Scamps, 2012).…”