1
|
Suga N, Murakami A, Arimitsu H, Shiogama K, Tanaka S, Ito M, Kato Y. Elevation of the serotonin-derived quinone, tryptamine-4,5-dione, in the intestine of ICR mice with dextran sulfate-induced colitis. J Clin Biochem Nutr 2021; 69:61-67. [PMID: 34376915 PMCID: PMC8325771 DOI: 10.3164/jcbn.20-161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/20/2020] [Indexed: 11/22/2022] Open
Abstract
Inflammatory bowel diseases, including Crohn's disease and ulcerative colitis, are chronic inflammatory disorders associated with oxidative stress. The intestines produce 5-hydroxytryptamine that may negatively affect disease state under inflammatory conditions when overproduced. 5-Hydroxytryptamine is a substrate for myeloperoxidase and is converted into reactive tryptamine-4,5-dione. Here, an experimental colitis model was established through oral administration of 5% dextran sulfate sodium to ICR mice for 7 days. Furthermore, the formation of tryptamine-4,5-dione in the colorectal mucosa/submucosa and colorectal tissue was analyzed by chemical and immunochemical methodologies. First, free tryptamine-4,5-dione in the homogenate was chemically trapped by o-phenylenediamine and analyzed as the stable phenazine derivative. Tryptamine-4,5-dione localization as adducted proteins in the colorectal tissue was immunohistochemically confirmed, and as demonstrated by both methods, this resulted in the significant increase of tryptamine-4,5-dione in dextran sulfate sodium-challenged mice compared with control mice. Immunohistochemical staining confirmed tryptamine-4,5-dione-positive staining at the myeloperoxidase accumulation site in dextran sulfate sodium-challenged mice colorectal tissue. The tryptamine-4,5-dione locus in the mice was partly matched with that of a specific marker for myeloperoxidase, halogenated tyrosine. Overall, the results possibly indicate that tryptamine-4,5-dione is generated by neutrophil myeloperoxidase in inflammatory tissue and may contribute to the development of inflammatory bowel disease.
Collapse
Affiliation(s)
- Naoko Suga
- Graduate School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Akira Murakami
- Graduate School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan.,Research Institute for Food and Nutritional Sciences, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Hideyuki Arimitsu
- Graduate School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan.,Research Institute for Food and Nutritional Sciences, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Kazuya Shiogama
- Department of Diagnostic Pathology II, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Sarasa Tanaka
- Graduate School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan.,Research Institute for Food and Nutritional Sciences, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Mikiko Ito
- Graduate School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan.,Research Institute for Food and Nutritional Sciences, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Yoji Kato
- Graduate School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan.,Research Institute for Food and Nutritional Sciences, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| |
Collapse
|
2
|
Kato Y, Suga N. Covalent adduction of endogenous and food-derived quinones to a protein: its biological significance. J Clin Biochem Nutr 2018; 62:213-220. [PMID: 29892159 PMCID: PMC5990407 DOI: 10.3164/jcbn.18-26] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 03/05/2018] [Indexed: 01/09/2023] Open
Abstract
There are many chemically reactive compounds, including quinone, in living systems and also food. Even after the ingestion of food polyphenols, quinones derived from catechol moieties could form endogenously in the body. Dopaquinone, dopamine quinone, estrogen-derived quinones, tryptamine-4,5-dione, and ubiquinone are examples of an endogenous quinone. These indicate that quinone is ubiquitously formed or present in living systems and food. Quinones can induce a variety of hazardous effects and also could have beneficial physiological effects. This review focuses on the chemical reactivity of quinone toward a biomolecule and its biological action.
Collapse
Affiliation(s)
- Yoji Kato
- Laboratory of Free Radical and Food Function, School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan.,Research Institute of Food and Nutrition, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Naoko Suga
- Laboratory of Free Radical and Food Function, School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| |
Collapse
|
3
|
Cytotoxic and cytoprotective effects of tryptamine-4,5-dione on neuronal cells: a double-edged sword. Free Radic Res 2018; 51:545-553. [PMID: 28503967 DOI: 10.1080/10715762.2017.1331038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Serotonin (5-hydroxytryptamine) is a putative substrate for myeloperoxidase, which may convert it into the reactive quinone tryptamine-4,5-dione (TD). In this study, we found that the viability of human SH-SY5Y neuroblastoma cells treated with 25 μM TD was increased to approximately 117%. On the other hand, the cell viability was significantly decreased by exposure to TD (150-200 μM), with an increase in intracellular reactive oxygen species (ROS). Interestingly, pre-treatment of SH-SY5Y cells with 100 μM TD prevented cell death and suppressed intracellular ROS generation evoked by the addition of hydrogen peroxide (H2O2). Expression of the phase-II antioxidant enzyme NAD(P)H: quinone oxidoreductase 1 and haem oxygenase 1 were upregulated by TD at a concentration of 50-100 μM. Nuclear factor erythroid 2-related factor 2 (Nrf2), the regulator of these enzyme, was translocated from the cytosol to the nucleus by 100 μM TD. In summary, moderate concentrations of TD may increase the self-defence capacity of neuronal cells against oxidative stress.
Collapse
|
4
|
Kato Y, Oki K, Suga N, Ono S, Ishisaka A, Miura Y, Kanazawa S, Naito M, Kitamoto N, Kettle AJ. A novel quinone derived from 5-hydroxyindoleacetic acid reacts with protein: Possible participation of oxidation of serotonin and its metabolite in the development of atherosclerosis. Free Radic Biol Med 2016; 101:500-510. [PMID: 27856348 DOI: 10.1016/j.freeradbiomed.2016.11.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 11/09/2016] [Accepted: 11/13/2016] [Indexed: 02/05/2023]
Abstract
The modification of 5-hydroxyindoleacetic acid (5HIAA) by myeloperoxidase with a xanthine oxidase system was investigated by chromatographic analyses. Two major products were identified as a dimer and quinone (indoleacetate dione) of 5HIAA. The formation of a quinone moiety was also confirmed by chemical trapping with o-phenylenediamine. In the presence of N-acetyl-cysteine (NAC), a quinone-NAC adduct was formed. When glyceraldehyde 3-phosphate dehydrogenase was exposed to the myeloperoxidase system with 5HIAA, quinone adducts were formed on the protein molecule. A monoclonal antibody was prepared using a quinone-modified protein as an immunogen to immunochemically detect the quinone on a protein. The established antibody recognized the quinone-NAC adduct, quinone-modified poly-L-lysine, and quinone-modified low-density lipoprotein. Quinone-modified proteins in human atherosclerotic lesions were immunohistochemically observed using the established antibody to the quinone and also a monoclonal antibody to tryptamine dione-modified protein, suggesting an occurrence of in vivo oxidation of serotonin and 5HIAA, accompanied by covalent adduction to biomolecules.
Collapse
Affiliation(s)
- Yoji Kato
- Graduate School of Human Science and Environment, University of Hyogo, Himeji, Hyogo, Japan.
| | - Kota Oki
- Graduate School of Human Science and Environment, University of Hyogo, Himeji, Hyogo, Japan
| | - Naoko Suga
- Graduate School of Human Science and Environment, University of Hyogo, Himeji, Hyogo, Japan
| | - Shigeki Ono
- Graduate School of Human Science and Environment, University of Hyogo, Himeji, Hyogo, Japan
| | - Akari Ishisaka
- Graduate School of Human Science and Environment, University of Hyogo, Himeji, Hyogo, Japan
| | - Yoko Miura
- Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Satoshi Kanazawa
- Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Michitaka Naito
- Division of Nutrition & Health, School and Graduate School of Life Studies, Sugiyama Jogakuen University, Nagoya, Aichi, Japan
| | - Noritoshi Kitamoto
- Graduate School of Human Science and Environment, University of Hyogo, Himeji, Hyogo, Japan
| | - Anthony J Kettle
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand
| |
Collapse
|
5
|
Kalogiannis M, Delikatny EJ, Jeitner TM. Serotonin as a putative scavenger of hypohalous acid in the brain. Biochim Biophys Acta Mol Basis Dis 2015; 1862:651-661. [PMID: 26699077 DOI: 10.1016/j.bbadis.2015.12.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 12/04/2015] [Accepted: 12/11/2015] [Indexed: 12/31/2022]
Abstract
Neurodegenerative disorders represent the culmination of numerous insults including oxidative stress. The long etiology of most of these disorders suggests that lessening the effects of one or more of the insults could significantly delay disease onset. Antioxidants have been tested as possible therapeutics for neurodegenerative disorders, but with little success. Here we report that serotonin acts as a scavenger of hypochlorous acid (HOCl) in the brain. Serotonin was shown to prevent the oxidation of 2-thio-5-nitrobenzoate by HOCl in a biphasic manner. The first phase was a partial scavenging that occurred at concentrations of serotonin that exceeded those of HOCl. (1)H-NMR studies indicated that HOCl chlorinates both the aryl and akyl nitrogen atoms of serotonin. Thus, the oxidation of 2-thio-5-nitrobenzoate that occurred during the first phase of scavenging is likely due to the formation of serotonergic chloramines. A second phase of scavenging occurred at concentrations of HOCl that exceeded those of serotonin. Under these conditions, the chlorinated serotonin polymerized and formed inert aggregates. Serotonin was further shown to prevent the loss of cells and cellular α-ketoglutarate dehydrogenase complex activity caused by HOCl. Extracellular concentrations of serotonin in the brain can be elevated with selective serotonin reuptake inhibitors and suggests that such compounds could be used to increase the cerebral antioxidant capacity. Acute administration of selective serotonin reuptake inhibitors to mice treated with endotoxin partially mitigated sickness behavior and protein chlorination in the brain. These observations suggest that serotonin may act to suppress chlorinative stress in the brain.
Collapse
Affiliation(s)
- Mike Kalogiannis
- Department of Neurosciences, Winthrop University Hospital, 222 Station Plaza, Mineola, NY 11501, USA.
| | - E James Delikatny
- Department of Radiology, University of Pennsylvania, 317 Anatomy Chemistry Building, 3620 Hamilton Walk, Pennsylvania, PA 19104, USA.
| | - Thomas M Jeitner
- Department of Neurosciences, Winthrop University Hospital, 222 Station Plaza, Mineola, NY 11501, USA; Department of Biochemistry and Molecular Biology, New York Medical College, Basic Sciences, 15 Dana Road, Valhalla, NY 10595, USA.
| |
Collapse
|
6
|
Kinetics of serotonin oxidation by heme–Aβ relevant to Alzheimer’s disease. J Biol Inorg Chem 2014; 19:1355-65. [DOI: 10.1007/s00775-014-1193-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/04/2014] [Indexed: 01/11/2023]
|
7
|
Kato Y, Ono S, Kitamoto N, Kettle AJ. Covalent modification of cytoskeletal proteins in neuronal cells by tryptamine-4,5-dione. Redox Biol 2014; 2:983-90. [PMID: 25460734 PMCID: PMC4215393 DOI: 10.1016/j.redox.2014.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/13/2014] [Indexed: 11/17/2022] Open
Abstract
Serotonin, 5-hydroxytryptamine, is a systemic bioactive amine that acts in the gut and brain. As a substrate of myeloperoxidase in vitro, serotonin is oxidized to tryptamine-4,5-dione (TD), which is highly reactive with thiols. In this work, we successively prepared a monoclonal antibody to quinone-modified proteins and found that the antibody preferentially recognizes the TD–thiol adduct. Using the antibody, we observed that the chloride ion, the predominant physiological substrate for myeloperoxidase in vivo, is not competitive toward the enzyme catalyzed serotonin oxidation process, suggesting that serotonin is a plausible physiological substrate for the enzyme in vivo. Immunocytochemical analyses revealed that TD staining was observed in the cytosol of SH-SY5Y neuroblastoma cells while blot analyses showed that some cellular proteins were preferentially modified. Pull-down analyses confirmed that the cytoskeletal proteins tubulins, vimentin, and neurofilament-L were modified. When pure tubulins were exposed to micromolar levels of synthetic TD, self-polymerization was initially enhanced and then suppressed. These results suggest that serotonin oxidation by myeloperoxidase or the action of other oxidants could cause functional alteration of cellular proteins, which may be related to neurodegeneration processes or irritable bowel syndrome. Antibody to quinone-modified protein was established and characterized. Modification of protein by quinone was dependent on myeloperoxidase but independent of chloride ion concentration. We immunochemically found that cellular proteins were preferentially modified. Quinone modulated polymerization of tubulins in vitro.
Collapse
Affiliation(s)
- Yoji Kato
- School of Human Science and Environment, University of Hyogo, Hyogo 670-0092, Japan.
| | - Shigeki Ono
- School of Human Science and Environment, University of Hyogo, Hyogo 670-0092, Japan.
| | - Noritoshi Kitamoto
- School of Human Science and Environment, University of Hyogo, Hyogo 670-0092, Japan.
| | - Anthony J Kettle
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand.
| |
Collapse
|
8
|
Kato Y, Peskin AV, Dickerhof N, Harwood DT, Kettle AJ. Myeloperoxidase Catalyzes the Conjugation of Serotonin to Thiols via Free Radicals and Tryptamine-4,5-dione. Chem Res Toxicol 2012; 25:2322-32. [DOI: 10.1021/tx300218f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yoji Kato
- School of Human Science
and
Environment, University of Hyogo, Himeji
670-0092, Japan
| | - Alexander V. Peskin
- Centre
for Free Radical Research,
Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand
| | - Nina Dickerhof
- Centre
for Free Radical Research,
Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand
| | - D. Tim Harwood
- Centre
for Free Radical Research,
Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand
| | - Anthony J. Kettle
- Centre
for Free Radical Research,
Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand
| |
Collapse
|
9
|
Yamamoto BK, Moszczynska A, Gudelsky GA. Amphetamine toxicities: classical and emerging mechanisms. Ann N Y Acad Sci 2010; 1187:101-21. [PMID: 20201848 DOI: 10.1111/j.1749-6632.2009.05141.x] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The drugs of abuse, methamphetamine and MDMA, produce long-term decreases in markers of biogenic amine neurotransmission. These decreases have been traditionally linked to nerve terminals and are evident in a variety of species, including rodents, nonhuman primates, and humans. Recent studies indicate that the damage produced by these drugs may be more widespread than originally believed. Changes indicative of damage to cell bodies of biogenic and nonbiogenic amine-containing neurons in several brain areas and endothelial cells that make up the blood-brain barrier have been reported. The processes that mediate this damage involve not only oxidative stress but also include excitotoxic mechanisms, neuroinflammation, the ubiquitin proteasome system, as well as mitochondrial and neurotrophic factor dysfunction. These mechanisms also underlie the toxicity associated with chronic stress and human immunodeficiency virus (HIV) infection, both of which have been shown to augment the toxicity to methamphetamine. Overall, multiple mechanisms are involved and interact to promote neurotoxicity to methamphetamine and MDMA. Moreover, the high coincidence of substituted amphetamine abuse by humans with HIV and/or chronic stress exposure suggests a potential enhanced vulnerability of these individuals to the neurotoxic actions of the amphetamines.
Collapse
Affiliation(s)
- Bryan K Yamamoto
- Department of Neurosciences, University of Toledo College of Medicine, Toledo, Ohio 43614, USA.
| | | | | |
Collapse
|
10
|
Serotonin as a physiological substrate for myeloperoxidase and its superoxide-dependent oxidation to cytotoxic tryptamine-4,5-dione. Biochem J 2009; 425:285-93. [PMID: 19828014 DOI: 10.1042/bj20090776] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
During inflammatory events, neutrophils and platelets interact to release a variety of mediators. Neutrophils generate superoxide and hydrogen peroxide, and also discharge the haem enzyme myeloperoxidase. Among numerous other mediators, platelets liberate serotonin (5-hydroxytryptamine), which is a classical neurotransmitter and vasoactive amine that has significant effects on inflammation and immunity. In the present study, we show that serotonin is a favoured substrate for myeloperoxidase because other physiological substrates for this enzyme, including chloride, did not affect its rate of oxidation. At low micromolar concentrations, serotonin enhanced hypochlorous acid production by both purified myeloperoxidase and neutrophils. At higher concentrations, it almost completely blocked the formation of hypochlorous acid. Serotonin was oxidized to a dimer by myeloperoxidase and hydrogen peroxide. It was also converted into tryptamine-4,5-dione, especially in the presence of superoxide. This toxic quinone was produced by stimulated neutrophils in a reaction that required myeloperoxidase. In plasma, stimulated human neutrophils oxidized serotonin to its dimer using the NADPH oxidase and myeloperoxidase. We propose that myeloperoxidase will oxidize serotonin at sites of inflammation. In doing so, it will impair its physiological functions and generate a toxic metabolite that will exacerbate inflammatory tissue damage. Consequently, oxidation of serotonin by myeloperoxidase may profoundly influence inflammatory processes.
Collapse
|
11
|
Quinton MS, Yamamoto BK. Causes and consequences of methamphetamine and MDMA toxicity. AAPS JOURNAL 2006; 8:E337-47. [PMID: 16796384 PMCID: PMC3231568 DOI: 10.1007/bf02854904] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Methamphetamine (METH) and its derivative 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) are 2 substituted amphetamines with very high abuse liability in the United States. These amphetamine-like stimulants have been associated with loss of multiple markers for dopaminergic and serotonergic terminals in the brain. Among other causes, oxidative stress, excitotoxicity and mitochondrial dysfunction appear to play a major role in the neurotoxicity produced by the substituted amphetamines. The present review will focus on these events and how they interact and converge to produce the monoaminergic depletions that are typically observed after METH or MDMA administration. In addition, more recently identified consequences of METH or MDMA-induced oxidative stress, excitotoxicity, and mitochondrial dysfunction are described in relation to the classical markers of METH-induced damage to dopamine terminals.
Collapse
Affiliation(s)
- Maria S. Quinton
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Room L-613, 715 Albany Street, 02118 Boston, MA
| | - Bryan K. Yamamoto
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Room L-613, 715 Albany Street, 02118 Boston, MA
| |
Collapse
|
12
|
Kovacic P, Cooksy AL. Unifying mechanism for toxicity and addiction by abused drugs: electron transfer and reactive oxygen species. Med Hypotheses 2005; 64:357-66. [PMID: 15607571 DOI: 10.1016/j.mehy.2004.07.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Accepted: 07/12/2004] [Indexed: 11/26/2022]
Abstract
Abused drugs are of grave concern throughout the world for a variety of reasons. Although impressive advances have been made, there are many unknown mechanistic aspects. This report presents a novel hypothesis based on a unifying theme for action of the major classes of abused drugs, in addition to commonly abused therapeutic drugs. The approach is based on electron transfer (ET), reactive oxygen species (ROS), and oxidative stress (OS). It is significant that physiologically active substances generally incorporate ET functionalities, either per se, or more usually in their metabolites. In order to achieve ET in vivo, the reduction potential must be more positive than -0.5 V, which is the case for metabolites of abused drugs, except for special cases. Since the ET process is catalytic, only small quantities of agent are needed for generation of large amounts of ROS during redox cycyling. Bioaction with cellular materials could entail ET alone or participation of ROS. In the abused category, among the main classes of ET functionalities are quinones and iminiums, with alpha-dicarbonyl and nitroxyl radical being rarer. Nicotine yields nicotine iminium, myosmine iminium, and DNA base iminium via alkylation by a metabolic nitrosamine. In the case of alcohol, diacetyl (an alpha-dicarbonyl) is formed, which can lead to conjugated imine (or iminium) by condensation with pri-amine of protein. Phencyclidine is unusual since the iminium product is non-conjugated. However, data indicate that the conformation present at the binding site can accommodate delocalization of the derived radical. For cocaine, various metabolites may play a role: iminium, nitroxyl radical, nitrosonium and formaldehyde. Dealkylation of the ether moiety of ecstasy provides a catechol function capable of redox cycling with the o-quinone partner. Amphetamine and methamphetamine also appear to function by way of the catechol route, as well as morphine and heroin. Tetrahydrocannabinol produces an epoxide, a functionality capable of DNA base alkylation accompanied by ROS. LSD undergoes oxidation to a phenol which may be a quinone precursor. Therapeutic drugs display the indicated metabolic relationships: benzodiazepines, iminium; phenytoin, quinone; phenobarbital, catechol; aspirin, catechol and hydroquinone; acetaminophen, iminoquinone. Extensive evidence exists for formation of ROS, organ injury by OS, depletion of AOs, and protection by AOs for the various drugs. There is also discussion of computational approaches, addiction mechanism and prevention, and health promotion.
Collapse
Affiliation(s)
- Peter Kovacic
- Department of Chemistry, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182-1030, USA.
| | | |
Collapse
|