The continuing goal of this competitive renewal application is to elucidate how aging causes well defined deficits in brain neurotransmitter release, focusing on the cholinergic system. As we explore this problem further at the biochemical level, new insights are provided about the regulation of the neurotransmitter-release process and its modulation in normal as well as senescent animals. The focus of the next four years shifts from that of calcium- fluxes and potency generally to that of the modulatory role of protein kinase C in these release-deficits. Our results and others suggest that this enzyme is a nodal point for the effects of aging and membrane peroxidation on transmitter release. Specifically, we propose to answer the following questions: 1. Does aging affect protein kinase C activity in different brain regions and preparations similarly? 2. How does aging interfere with the phorbol ester-induced release of acetylcholine (ACh) and the translocation of protein kinase C? 3. Does aging affect the potency of calcium ionophores with respect to protein kinase C translocation? 4. Does infusion of protein kinase C directly into synaptosomes affect protein phosphorylation and ACh release? 5. Does aging affect the protein kinase C-mediated phosphorylation of proteins in synaptosomes in situ? 6. Does phosphatidylserine restore age-related deficits in protein kinase C translocation to normal? 7. Does exogenous synaptosomal membrane peroxidation mimic the effects of aging on protein kinase C activities as it does ACh release and membrane fluidity? These studies combine a variety of enzyme assays and pharmacological approaches used in my laboratory, along with a viral coat infusion procedure adapted to infuse enzymes or other macromolecules into nerve terminals. We will continue to use diluted synaptosomes as the preparation of choice for reasons described in the previous grant.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
2R01AG006226-04
Application #
3117153
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1987-01-15
Project End
1993-12-31
Budget Start
1990-01-01
Budget End
1990-12-31
Support Year
4
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Florida
Department
Type
Schools of Medicine
DUNS #
073130411
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Meyer, E M; Judkins, J H; Momol, A E et al. (1994) Effects of peroxidation and aging on rat neocortical ACh-release and protein kinase C. Neurobiol Aging 15:63-7
Evans, S M; Kushner, P D; Meyer, E M (1993) Actions of a monoclonal antibody Tor 23 on rat brain presynaptic cholinergic processes. Neurochem Res 18:339-44
Meyer, E M; Bryant, S O; Wang, R H et al. (1993) Characterization of [3H]vesamicol binding in rat brain preparations. Neurochem Res 18:1067-72
Meyer, E M; Judkins, J H; Hardwick, E O (1993) Recovery of [3H]acetylcholine synthesis after AF64A-treatment in primary, neuron-enriched, rat septal-hippocampal and striatal cultures. Brain Res Dev Brain Res 74:51-6
Poulakos, J J; Millard, W J; Meyer, E M (1993) Modulation of neuropeptide Y expression in rat brain neuronal cultures. Brain Res Dev Brain Res 74:25-9
Meyer, E M; Judkins, J H (1993) Effects of membrane peroxidation on [3H]acetylcholine release in rat cerebral cortical synaptosomes. Neurochem Res 18:1047-50
Meyer, E M; Judkins, J H (1993) The development of age-related deficits in several presynaptic processes associated with brain [3H]acetylcholine release. Mech Ageing Dev 72:119-28
de Fiebre, C M; Bryant, S O; Notabartolo, D et al. (1993) Fusogenic properties of Sendai virosome envelopes in rat brain preparations. Neurochem Res 18:1089-94
Arendash, G W; Millard, W J; Dawson Jr, R et al. (1989) Different long-term effects of bilateral and unilateral nucleus basalis lesions on rat cerebral cortical neurotransmitter content. Neurochem Res 14:1113-8