title: Restoration of calcium influx corrects membrane hyperexcitability in injured rat dorsal root ganglion neurons.
abstract: BACKGROUND
  We have previously shown that a decrease of inward Ca(2+) flux (I(Ca)) across the sensory neuron plasmalemma, such as happens after axotomy, increases neuronal excitability. From this, we predicted that increasing I(Ca) in injured neurons should correct their hyperexcitability.
  
  
  METHODS
  The influence of increased or decreased I(Ca) upon membrane biophysical variables and excitability was determined during recording from A-type neurons in nondissociated dorsal root ganglia after spinal nerve ligation using an intracellular recording technique.
  
  
  RESULTS
  When the bath Ca(2+) level was increased to promote I(Ca), the after-hyperpolarization was decreased and repetitive firing was suppressed, which also followed amplification of Ca(2+)-activated K(+) current with selective agents NS1619 and NS309. A decreased external bath Ca(2+) concentration had the opposite effects, similar to previous observations in uninjured neurons.
  
  
  CONCLUSIONS
  These findings indicate that at least a part of the hyperexcitability of somatic sensory neurons after axotomy is attributable to diminished inward Ca(2+) flux, and that measures to restore I(Ca) may potentially be therapeutic for painful peripheral neuropathy.
authors: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA. qhogan@mcw.edu
authors: Quinn
authors: Q
authors: Hogan
authors: Philipp
authors: P
authors: Lirk
authors: Mark
authors: M
authors: Poroli
authors: Marcel
authors: M
authors: Rigaud
authors: Andreas
authors: A
authors: Fuchs
authors: Patrick
authors: P
authors: Fillip
authors: Marko
authors: M
authors: Ljubkovic
authors: Geza
authors: G
authors: Gemes
authors: Damir
authors: D
authors: Sapunar
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001562:Benzimidazoles / Q000494:pharmacology; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000196:embryology*; D007211:Indoles / Q000494:pharmacology; D008297:Male; D008954:Models, Biological; D009474:Neurons / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism; D010091:Oximes / Q000494:pharmacology; D011188:Potassium / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013127:Spinal Nerves / Q000473:pathology
chemical_list: C493327:6,7-dichloro-1H-indole-2,3-dione 3-oxime; D001562:Benzimidazoles; D007211:Indoles; D010091:Oximes; C086491:NS 1619; D011188:Potassium; D002118:Calcium