Axotomy-induced expression of calcium-activated chloride current in subpopulations of mouse dorsal root ganglion neurons.
Whole cell patch-clamp recordings of calcium-activated chloride current [ICl(Ca)] were made from adult sensory neurons of naive and axotomized mouse L4-L6 lumbar dorsal root ganglia after 1 day of culture in vitro. A basal ICl(Ca) was specifically expressed in a subset of naive medium-diameter neurons (30-40 microm). Prior nerve injury, induced by sciatic nerve transection 5 days before experiments, increased both ICl(Ca) amplitude and its expression in medium-diameter neurons. Moreover, nerve injury also induced ICl(Ca) expression in a new subpopulation of neurons, the large-diameter neurons (40-50 microm). Small-diameter neurons (inferior to 30 microm) never expressed ICl(Ca). Regulated ICl(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 ICl(Ca) expression in axotomized neurons. Regenerative growth and the induction of ICl(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 ICl(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.
André
Sylvain
S
Institut National de la Santé et de la Recherche Médicale U-583, Université Montpellier II, 34095, Montpellier 5, France.
Boukhaddaoui
Hassan
H
Campo
Brice
B
Al-Jumaily
Mohammed
M
Mayeux
Véronique
V
Greuet
Denis
D
Valmier
Jean
J
Scamps
Frédérique
F
D000818:Animals; D019771:Axotomy; D020013:Calcium Signaling / Q000502:physiology*; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D018118:Chloride Channels / Q000096:biosynthesis*; D004594:Electrophysiology; D005260:Female; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D009416:Nerve Regeneration / Q000502:physiology; D016501:Neurites / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D012584:Sciatic Nerve / Q000502:physiology; D015854:Up-Regulation
D018118:Chloride Channels