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Pyridoxine megavitaminosis produces degeneration of peripheral sensory neurons (sensory neuronopathy) in the dog.
Krinke-G; Schaumburg-HH; Spencer-PS; Suter-J; Thomann-P; Hess-R
Neurotoxicology 1981 Jan; 2(1):13-24
Nervous system degeneration was investigated in six Beagle-dogs of both sexes who were intoxicated with daily doses of 300mg/kg pyridoxol-hydrochloride (58560); two dogs served as controls and received vehicle only. The animals were sacrificed on days three, 15, 22, 29, 51, and 78 of treatment. Between the fourth and ninth days of intoxication the animals developed a swaying gait with severe ataxia developing between days eight to 30. Morphological abnormalities were detected in dorsal root and Gasserian ganglia and were confined to their neurons and processes. Initial morphological abnormalities were focal clearings in the cytoplasm of large neurons. The process of neuronal damage predominately affected large ganglion cells, and even in the animals with the most advanced changes, many neurons appeared unaffected. Wallerian like degeneration was present throughout the length of the nerve fibers in the dorsal roots, dorsal columns of the spinal cord, descending tract of the trigeminal nerve and in scattered fibers of all peripheral nerves sampled. While the large diameter neurons were particularly vulnerable to pyridoxine (65236) many smaller diameter neurons appeared unaffected, even after prolonged intoxication. The pattern of nervous system degeneration produced by pyridoxine was best described as a peripheral sensory neuronopathy, similar in distribution to changes observed in experimental doxorubicin intoxication. Such disruption can cause cell death, making them unable to maintain their axons.
NIOSH-Publication; NIOSH-Grant; Neurotoxic-effects; Laboratory-animals; Cell-damage; Neuropathology; Nervous-system-disorders; Vitamins; Enzymes; Dietary-effects
Neuroscience Albert Einstein College 1410 Pelham Parkway Bronx, N Y 10461
Issue of Publication
Neurotoxic Disorders; Neurotoxic-effects;
Yeshiva University, New York, New York
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division