The aim of this project is to employ electrochemical and other analytical techniques to investigate the oxidation chemistry of naturally occurring or otherwise biologically significant indoles. These will include the 5-hydrosylated metabolites of tryptophan, N-methylated indoles (such as bufotenin) which are implicated in the etiology of schizophrenia and depression, and 5,6- and 5,7-dihydrosytryptamines (5,6- and 5,7-DHT) which are powerful neurotoxins. Anomalous, minor oxidation pathways of, for example, the enurotransmitter 5-hydrosytryptamine have been speculated to play a role in some mental disorders. Similarly, the neurotoxicity of 5,6- and 5,7DHT is thought to be due to reactions of their reactive autoxidation products in the CNA. Many of these indoles undergo oxidation reactions in biological systems yet virtually nothing is known about the mechanisms and products of these processes. Modern electroanalytical techniques will be used to elucidate the nature of the primary oxidation step and the identity and properties of transient intermediates. Longer lived intermediates will be further studied using spectral and chromatographic methods, particularly GC-MS and LC-MS techniques. Reaction products will be isolated and identified using a wide range of analytical techniques including column chromatography, HPLC, U.V.-vis, I.R., NMR and mass spectrometry. Evidence concerning the biological relevance of such studies will be obtained by investigating the oxidation of these indoles with various CNS enzymes and critically comparing the courses of the electrochemical and enzymatic oxidations. In vivo evaluations of the neurotoxic properties of the many new products formed by electrochemical and enzymatic oxidation are planned. Electrochemical and other analytical techniques will be used to study the interactions of the very reactive primary oxidation products of indoles (quinones, quinoneimines, methyleneimines) with nucleophiles commonly found in CNS tissue (thiols, amino acids, water). The long range goal is to develop a fundamental understanding of the oxidation chemistry of biologically significant indoles. This, in turn, could provide a basis for understanding the oxidation chemistry of such indoles in living systems which might give important insights into a chemical basis for some mental illnesses and other disease states.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM032367-04
Application #
3281124
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
1983-09-15
Project End
1991-08-31
Budget Start
1986-09-01
Budget End
1987-08-31
Support Year
4
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Oklahoma Norman
Department
Type
Schools of Arts and Sciences
DUNS #
848348348
City
Norman
State
OK
Country
United States
Zip Code
73019
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Jiang, Xiang-Rong; Dryhurst, Glenn (2002) Inhibition of the alpha-ketoglutarate dehydrogenase and pyruvate dehydrogenase complexes by a putative aberrant metabolite of serotonin, tryptamine-4,5-dione. Chem Res Toxicol 15:1242-7
Horstman, Joseph A; Wrona, Monika Z; Dryhurst, Glenn (2002) Further insights into the reaction of melatonin with hydroxyl radical. Bioorg Chem 30:371-82
Wrona, M Z; Dryhurst, G (2001) A putative metabolite of serotonin, tryptamine-4,5-dione, is an irreversible inhibitor of tryptophan hydroxylase: possible relevance to the serotonergic neurotoxicity of methamphetamine. Chem Res Toxicol 14:1184-92
Li, H; Dryhurst, G (2001) Oxidative metabolites of 5-S-cysteinyldopamine inhibit the pyruvate dehydrogenase complex. J Neural Transm 108:1363-74
Dryhurst, G (2001) Are dopamine, norepinephrine, and serotonin precursors of biologically reactive intermediates involved in the pathogenesis of neurodegenerative brain disorders? Adv Exp Med Biol 500:373-96
Shen, X M; Li, H; Dryhurst, G (2000) Oxidative metabolites of 5-S-cysteinyldopamine inhibit the alpha-ketoglutarate dehydrogenase complex: possible relevance to the pathogenesis of Parkinson's disease. J Neural Transm 107:959-78

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