this is a new R01 proposal to study mechanisms of excitotoxicity at the cellular level. The author proposes to - 1 - use confocal microscopy as well as specific intracellular dyes to dissect the involvement of calcium, mitochondria and the production of free radicals as related to neuronal death. The fundamental hypothesis is that there is functional and temporal coupling between an NMDA receptor stimulation and cytosolic calcium accumulation, intramitochondrial accumulation, production of free radicals, mitochondrial depolarization, opening of the mitochondrial transition pore and eventual neuronal death. The author proposes four specific aims.
In specific aim 1 he will use primary cultures of neurons as well as laser scanning confocal microscopy to examine and correlate the above mentioned sequence temporally.
In specific aim 2 he will test the hypothesis that activation of nonNMDA receptors or voltage dependent calcium channels will have less of an effect than an NMDA receptor activation on mitochondrial calcium, free radical production and membrane potential.
Specific aim 3 will determine whether inhibition of the electron transport chain will impair the ability of mitochondria to accumulate calcium as well as to cause abnormal elevation of cytosolic calcium and to facilitate opening of the permeability transition pore. Lastly the author will examine lymphoblastoid cell lines derived from patients with known mitochondrial defects to determine whether these cells lines exhibit abnormal mitochondrial calcium accumulation, membrane potential and free radical production. Furthermore he will then transfect these lymphoblasts with an NMDA receptor to determine whether they are abnormally sensitive to receptor activation as compared to lymphoblastoid cell lines from normal controls.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
1R01AG014648-01
Application #
2370642
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Oliver, Eugene J
Project Start
1997-08-01
Project End
2002-05-31
Budget Start
1997-08-01
Budget End
1998-05-31
Support Year
1
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Emory University
Department
Neurology
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Panov, Alexander V; Burke, James R; Strittmatter, Warren J et al. (2003) In vitro effects of polyglutamine tracts on Ca2+-dependent depolarization of rat and human mitochondria: relevance to Huntington's disease. Arch Biochem Biophys 410:1-6
Betarbet, Ranjita; Sherer, Todd B; Greenamyre, J Timothy (2002) Animal models of Parkinson's disease. Bioessays 24:308-18
Stephans, Stacy E; Miller, Gary W; Levey, Allan I et al. (2002) Acute mitochondrial and chronic toxicological effects of 1-methyl-4-phenylpyridinium in human neuroblastoma cells. Neurotoxicology 23:569-80
Sherer, Todd B; Betarbet, Ranjita; Greenamyre, J Timothy (2002) Environment, mitochondria, and Parkinson's disease. Neuroscientist 8:192-7
Panov, Alexander V; Gutekunst, Claire-Anne; Leavitt, Blair R et al. (2002) Early mitochondrial calcium defects in Huntington's disease are a direct effect of polyglutamines. Nat Neurosci 5:731-6
Greenamyre, J T; Sherer, T B; Betarbet, R et al. (2001) Complex I and Parkinson's disease. IUBMB Life 52:135-41
Greenamyre, J T; MacKenzie, G; Peng, T I et al. (1999) Mitochondrial dysfunction in Parkinson's disease. Biochem Soc Symp 66:85-97
Peng, T I; Greenamyre, J T (1998) Privileged access to mitochondria of calcium influx through N-methyl-D-aspartate receptors. Mol Pharmacol 53:974-80