Pyridoxine-induced toxicity in rats: a stereological quantification of the sensory neuropathy

Exp Neurol. 2004 Nov;190(1):133-44. doi: 10.1016/j.expneurol.2004.07.013.


Excess ingestion of pyridoxine (vitamin B6) causes a severe sensory neuropathy in humans. The mechanism of action has not been fully elucidated, and studies of pyridoxine neuropathy in experimental animals have yielded disparate results. Pyridoxine intoxication appears to produce a neuropathy characterized by necrosis of dorsal root ganglion (DRG) sensory neurons and degeneration of peripheral and central sensory projections, with large diameter neurons being particularly affected. The major determinants affecting the severity of the pyridoxine neuropathy appear to be duration and dose of pyridoxine administration, differential neuronal vulnerability, and species susceptibility. The present study used design-based stereological techniques in conjunction with electrophysiological measures to quantify the morphological and physiological changes that occur in the DRG and the distal myelinated axons of the sciatic nerve following pyridoxine intoxication. This combined stereological and electrophysiological method demonstrates a general approach that could be used for assessing the correlation between pathophysiological and functional parameters in animal models of toxic neuropathy.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Count / statistics & numerical data
  • Cell Size / drug effects
  • Disease Models, Animal
  • Disease Progression
  • Electrophysiology
  • Ganglia, Spinal / pathology
  • H-Reflex / drug effects
  • Male
  • Motor Neurons / drug effects
  • Motor Neurons / pathology
  • Nerve Fibers, Myelinated / drug effects
  • Nerve Fibers, Myelinated / pathology
  • Neural Conduction / drug effects
  • Neurodegenerative Diseases / chemically induced*
  • Neurodegenerative Diseases / pathology*
  • Neurodegenerative Diseases / physiopathology
  • Psychomotor Performance / drug effects
  • Pyridoxine / toxicity*
  • Rats
  • Rats, Sprague-Dawley
  • Sciatic Nerve / drug effects
  • Sciatic Nerve / pathology
  • Sensation Disorders / chemically induced*
  • Sensation Disorders / pathology*
  • Sensation Disorders / physiopathology


  • Pyridoxine