Mechanisms of Injury in the Central Nervous System

Martin A. Philbert, Melvin Billingsley, Kenneth R. Reuhl

Research output: Contribution to journalArticle

100 Citations (Scopus)

Abstract

Neurotoxicants with similar structural features or common mechanisms of chemical action frequently produce widely divergent neuropathologic outcomes. Methylmercury (MeHg) produces marked cerebellar dysmorphogenesis during critical periods of development. The pathologic picture is characterized by complete architectural disruption of neuronal elements within the cerebellum. MeHg binds strongly to protein and soluble sulphydryl groups. Binding to microtubular -SH groups results in catastrophic depolymerization of immature tyrosinated microtubules. However, more mature acetylated microtubules are resistant to MeHg-induced depolymerization. In contrast to MeHg, the structurally similar organotin trimethyltin (TMT) elicits specific apoptotic destruction of pyramidal neurons in the CA3 region of the hippocampus and in other limbic structures. Expression of the phylogenetically conserved protein stannin is required for development of TMT-induced lesions. Inhibition of expression using antisense oligonucleotides against stannin protects neurons from the effects of TMT, suggesting that this protein is required for expression of neurotoxicity. However, expression of stannin alone is insufficient for induction of apoptotic pathways in neuronal populations. The aromatic nitrocompound 1,3-dinitrobenzene (DNB) has 2 independent nitro groups that can redox cycle in the presence of molecular oxygen. Despite its ability to deplete neural glutathione stores, DNB produces edematous gliovascular lesions in the brain stem of rats. Glial cells are susceptible despite high concentrations of reduced glutathione compared with neuronal somata in the central nervous system (CNS). The severity of lesions produced by DNB is modulated by the activity of neurons in the affected pathways. The inherent discrepancy between susceptibility of neuronal and glial cell populations is likely mediated by differential control of the mitochondrial permeability transition in astrocytes and neurons. Lessons learned in the mechanistic investigation of neurotoxicants suggest caution in the evaluation and interpretation of structure-activity relationships, eg, TMT, MeHg, and DNB all induce oxidative stress, whereas TMT and triethyltin produce neuronal damage and myelin edema, respectively. The precise CNS molecular targets of cell-specific lipophilic neurotoxicants remain to be determined.

Original languageEnglish (US)
Pages (from-to)43-53
Number of pages11
JournalToxicologic Pathology
Volume28
Issue number1
DOIs
StatePublished - Jan 1 2000

Fingerprint

Neurology
Central Nervous System
Neurons
Wounds and Injuries
Depolymerization
Microtubules
Neuroglia
Glutathione
Pharmacologic Actions
Proteins
Oxidative stress
Molecular oxygen
Antisense Oligonucleotides
Pyramidal Cells
Carisoprodol
Structure-Activity Relationship
Myelin Sheath
Astrocytes
Cerebellum
Population

All Science Journal Classification (ASJC) codes

  • Pathology and Forensic Medicine
  • Molecular Biology
  • Toxicology
  • Cell Biology

Cite this

Philbert, Martin A. ; Billingsley, Melvin ; Reuhl, Kenneth R. / Mechanisms of Injury in the Central Nervous System. In: Toxicologic Pathology. 2000 ; Vol. 28, No. 1. pp. 43-53.
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Philbert, MA, Billingsley, M & Reuhl, KR 2000, 'Mechanisms of Injury in the Central Nervous System', Toxicologic Pathology, vol. 28, no. 1, pp. 43-53. https://doi.org/10.1177/019262330002800107

Mechanisms of Injury in the Central Nervous System. / Philbert, Martin A.; Billingsley, Melvin; Reuhl, Kenneth R.

In: Toxicologic Pathology, Vol. 28, No. 1, 01.01.2000, p. 43-53.

Research output: Contribution to journalArticle

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