Studies is this proposal are directed to understanding the sequential biochemical and early ultrastructural events induced by methyl mercury in the cerebellum, in situ; in isolated cerebellar perikaryal cells and cell-free protein translation systems. Our studies have revealed both in vivo and in vitro methyl mercury inhibition of cell-free translation at the level of elongation. We will elucidate the molecular locus of this defect in the process of elongation using reconstitution experiments with the elongation factors (eEF-1 and eEF-2) following their isolation and purification. An early defect in cerebellar granule cell RNA synthesis requires determination of the significance of this molecular locus with especial reference to [3H]-uridine uptake, phosphorylation reactions and sensitivity of the individual RNA polymerases to methyl mercury after in vivo and in vitro intoxication. These biochemical studies will be correlated with stereologic morphometry of Purkinje and granule cell ultrastructure in vivo and also is isolated cerebellar perikaryal cell preparation after short term culture in the presence of methyl mercury. Identification of the mercurial induced biochemical and ultrastructural lesions will provide a means for assay of sub-symptomatic neurotoxicity and lead to a more rational treatment protocol. Mercurial interaction with the process of elongation will increase our understanding of this biochemical sequence in eukaryotic brain translation, its regulation and role in initiating cell injury.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES002573-05
Application #
3249902
Study Section
Toxicology Study Section (TOX)
Project Start
1981-04-01
Project End
1987-03-31
Budget Start
1985-04-01
Budget End
1986-03-31
Support Year
5
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Type
Schools of Medicine
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Verity, M A; Sarafian, T; Pacifici, E H et al. (1994) Phospholipase A2 stimulation by methyl mercury in neuron culture. J Neurochem 62:705-14
Sarafian, T A (1993) Methyl mercury increases intracellular Ca2+ and inositol phosphate levels in cultured cerebellar granule neurons. J Neurochem 61:648-57
Verity, M A; Torres, M; Sarafian, T (1991) Paradoxical potentiation by low extracellular Ca2+ of acute chemical anoxic neuronal injury in cerebellar granule cell culture. Mol Chem Neuropathol 15:217-33
Sarafian, T; Verity, M A (1991) Oxidative mechanisms underlying methyl mercury neurotoxicity. Int J Dev Neurosci 9:147-53
Sarafian, T; Verity, M A (1990) Methyl mercury stimulates protein 32P phospholabeling in cerebellar granule cell culture. J Neurochem 55:913-21
Verity, M A; Sarafian, T S; Guerra, W et al. (1990) Ionic modulation of triethyllead neurotoxicity in cerebellar granule cell culture. Neurotoxicology 11:415-26
Sarafian, T; Verity, M A (1990) Altered patterns of protein phosphorylation and synthesis caused by methyl mercury in cerebellar granule cell culture. J Neurochem 55:922-9
Sarafian, T; Hagler, J; Vartavarian, L et al. (1989) Rapid cell death induced by methyl mercury in suspension of cerebellar granule neurons. J Neuropathol Exp Neurol 48:1-10
Seidman, B C; Olsen, R W; Verity, M A (1987) Triethyllead inhibits gamma-aminobutyric acid binding to uptake sites in synaptosomal membranes. J Neurochem 49:415-20
Seidman, B C; Verity, M A (1987) Selective inhibition of synaptosomal gamma-aminobutyric acid uptake by triethyllead: role of energy transduction and chloride ion. J Neurochem 48:1142-9

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