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Piel S, Janowska JI, Ward JL, McManus MJ, Aronowitz DI, Janowski PK, Starr J, Hook JN, Hefti MM, Clayman CL, Elmér E, Hansson MJ, Jang DH, Karlsson M, Ehinger JK, Kilbaugh TJ. Succinate prodrugs as treatment for acute metabolic crisis during fluoroacetate intoxication in the rat. Mol Cell Biochem 2023; 478:1231-1244. [PMID: 36282352 PMCID: PMC10540239 DOI: 10.1007/s11010-022-04589-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 10/12/2022] [Indexed: 10/31/2022]
Abstract
Sodium fluoroacetate (FA) is a metabolic poison that systemically inhibits the tricarboxylic acid (TCA) cycle, causing energy deficiency and ultimately multi-organ failure. It poses a significant threat to society because of its high toxicity, potential use as a chemical weapon and lack of effective antidotal therapy. In this study, we investigated cell-permeable succinate prodrugs as potential treatment for acute FA intoxication. We hypothesized that succinate prodrugs would bypass FA-induced mitochondrial dysfunction, provide metabolic support, and prevent metabolic crisis during acute FA intoxication. To test this hypothesis, rats were exposed to FA (0.75 mg/kg) and treated with the succinate prodrug candidate NV354. Treatment efficacy was evaluated based on cardiac and cerebral mitochondrial respiration, mitochondrial content, metabolic profiles and tissue pathology. In the heart, FA increased concentrations of the TCA metabolite citrate (+ 4.2-fold, p < 0.01) and lowered ATP levels (- 1.9-fold, p < 0.001), confirming the inhibition of the TCA cycle by FA. High-resolution respirometry of cardiac mitochondria further revealed an impairment of mitochondrial complex V (CV)-linked metabolism, as evident by a reduced phosphorylation system control ratio (- 41%, p < 0.05). The inhibition of CV-linked metabolism is a novel mechanism of FA cardiac toxicity, which has implications for drug development and which NV354 was unable to counteract at the given dose. In the brain, FA induced the accumulation of β-hydroxybutyrate (+ 1.4-fold, p < 0.05) and the reduction of mitochondrial complex I (CI)-linked oxidative phosphorylation (OXPHOSCI) (- 20%, p < 0.01), the latter of which was successfully alleviated by NV354. This promising effect of NV354 warrants further investigations to determine its potential neuroprotective effects.
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Affiliation(s)
- Sarah Piel
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA.
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA.
| | - Joanna I Janowska
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - J Laurenson Ward
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Meagan J McManus
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Danielle I Aronowitz
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Piotr K Janowski
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Jonathan Starr
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Jordan N Hook
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, USA
| | - Marco M Hefti
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, USA
| | - Carly L Clayman
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Eskil Elmér
- Abliva AB, Lund, Sweden
- Mitochondrial Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Magnus J Hansson
- Abliva AB, Lund, Sweden
- Mitochondrial Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - David H Jang
- Department of Emergency Medicine, Division of Medical Toxicology, University of Pennsylvania School of Medicine, Philadelphia, USA
| | | | - Johannes K Ehinger
- Mitochondrial Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
- Otorhinolaryngology, Head and Neck Surgery, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, Lund, Sweden
| | - Todd J Kilbaugh
- Resuscitation Science Center of Emphasis, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, USA
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MacDonald AJ, Ellacott KLJ. Astrocytes in the nucleus of the solitary tract: Contributions to neural circuits controlling physiology. Physiol Behav 2020; 223:112982. [PMID: 32535136 PMCID: PMC7378570 DOI: 10.1016/j.physbeh.2020.112982] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 05/04/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022]
Abstract
The nucleus of the solitary tract (NTS) is the primary brainstem centre for the integration of physiological information from the periphery transmitted via the vagus nerve. In turn, the NTS feeds into downstream circuits regulating physiological parameters. Astrocytes are glial cells which have key roles in maintaining CNS tissue homeostasis and regulating neuronal communication. Recently an increasing number of studies have implicated astrocytes in the regulation of synaptic transmission and physiology. This review aims to highlight evidence for a role for astrocytes in the functions of the NTS. Astrocytes maintain and modulate NTS synaptic transmission contributing to the control of diverse physiological systems namely cardiovascular, respiratory, glucoregulatory, and gastrointestinal. In addition, it appears these cells may have a role in central control of feeding behaviour. As such these cells are a key component of signal processing and physiological control by the NTS.
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Affiliation(s)
- Alastair J MacDonald
- Institute of Biomedical & Clinical Sciences, University of Exeter Medical School, Level 4, RILD, Barrack Rd, Exeter EX2 5DW, UK
| | - Kate L J Ellacott
- Institute of Biomedical & Clinical Sciences, University of Exeter Medical School, Level 4, RILD, Barrack Rd, Exeter EX2 5DW, UK.
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DeLey Cox VE, Hartog MA, Pueblo E, Racine M, Jennings L, Tressler J, Tuet WY, Stone S, Pierce SA, Thompson L, Dukes A, Hoard-Fruchey H, Wong B, McCranor BJ. Methylene blue and monosodium glutamate improve neurologic signs after fluoroacetate poisoning. Ann N Y Acad Sci 2020; 1479:196-209. [PMID: 32285953 DOI: 10.1111/nyas.14347] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 12/17/2022]
Abstract
Fluoroacetate (FA) is a tasteless, odorless, water-soluble metabolic poison with severe toxicological effects. Characterized in the mid-1900s, it has been used as a rodenticide but is comparably lethal to all mammals. Many countries have restricted its use, and modern-day accidental human exposures are rare, but recently, concerns have been raised about its application as a chemical weapon with no known antidote. A combined treatment of methylene blue (MB), an antioxidant, and monosodium glutamate (MSG), a precursor of the citric acid cycle substrate alpha-ketoglutarate, has been recommended as an effective countermeasure; however, no peer-reviewed articles documenting the efficacy of this therapy have been published. Using a rodent model, we assessed the effects of MB and MSG on the neurologic, cardiac, and pulmonary systems. Transcriptomic analysis was used to elucidate inflammatory pathway activation and guide bioassays, which revealed the advantages and disadvantages of these candidate countermeasures. Results show that MB and MSG can reduce neurologic signs observed in rats exposed to sodium FA and improve some effects of intoxication. However, while this strategy resolved some signs of intoxication, ultimately it was unable to significantly reduce lethality.
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Affiliation(s)
- Vanessa E DeLey Cox
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Matthew A Hartog
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Erin Pueblo
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Michelle Racine
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Laura Jennings
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Justin Tressler
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Wing Y Tuet
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Samuel Stone
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Samuel A Pierce
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Lily Thompson
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Aliyah Dukes
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Heidi Hoard-Fruchey
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Benjamin Wong
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Bryan J McCranor
- Pharmaceutical Sciences Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
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McCranor BJ, Young TD, Tressler J, Jennings L, Irwin J, Alli NA, Abilez MK, Stone S, Racine M, Devorak JL, Sciuto AM, Wong B. The Cardiopulmonary Effects of Sodium Fluoroacetate (1080) in Sprague-Dawley Rats. COGENT BIOLOGY 2019; 5:1568669. [PMID: 31595219 PMCID: PMC6782068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Sodium fluoroacetate (1080) is a highly toxic metabolic poison that has the potential because of its lack of defined color, odor, and taste and its high water solubility to be intentionally or unintentionally ingested through food adulteration. Although the mechanism of action for 1080 has been known since the 1950's, no known antidote exists. In an effort to better understand the cardiopulmonary impacts of 1080, we utilized whole-body plethysmography and telemeterized Sprague-Dawley rats which allowed for the real-time measurement of respiratory and cardiac parameters following exposure using a non-invasive assisted-drinking method. Overall, the animals showed marked depression of respiratory parameters over the course of 24 hours post-exposure and the development of hemorrhage in the lung tissue. Tidal volume was reduced by 30% in males and 60% in females at 24 hours post-exposure, and respiratory frequency was significantly depressed as well. In telemeterized female rats, we observed severe cardiac abnormalities, highlighted by a 50% reduction in heart rate, 75% reduction in systolic blood pressure, and a 3.5-fold lengthening of the QRS interval over the course of 24 hours. We also observed a reduction in core body temperature of nearly 15°C. Our study was able to describe the severe and pronounced effects of sodium fluoroacetate poisoning on cardiopulmonary function, the results of which indicate that both tissue specific and systemic deficits contribute to the toxicological progression of 1080 intoxication and will need to be accounted for when developing any potential countermeasure for 1080 poisoning.
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Rogers RC, McDougal DH, Ritter S, Qualls-Creekmore E, Hermann GE. Response of catecholaminergic neurons in the mouse hindbrain to glucoprivic stimuli is astrocyte dependent. Am J Physiol Regul Integr Comp Physiol 2018; 315:R153-R164. [PMID: 29590557 PMCID: PMC6087883 DOI: 10.1152/ajpregu.00368.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Hindbrain catecholaminergic (CA) neurons are required for critical autonomic, endocrine, and behavioral counterregulatory responses (CRRs) to hypoglycemia. Recent studies suggest that CRR initiation depends on hindbrain astrocyte glucose sensors (McDougal DH, Hermann GE, Rogers RC. Front Neurosci 7: 249, 2013; Rogers RC, Ritter S, Hermann GE. Am J Physiol Regul Integr Comp Physiol 310: R1102-R1108, 2016). To test the proposition that hindbrain CA responses to glucoprivation are astrocyte dependent, we utilized transgenic mice in which the calcium reporter construct (GCaMP5) was expressed selectively in tyrosine hydroxylase neurons (TH-GCaMP5). We conducted live cell calcium-imaging studies on tissue slices containing the nucleus of the solitary tract (NST) or the ventrolateral medulla, critical CRR initiation sites. Results show that TH-GCaMP5 neurons are robustly activated by a glucoprivic challenge and that this response is dependent on functional astrocytes. Pretreatment of hindbrain slices with fluorocitrate (an astrocytic metabolic suppressor) abolished TH-GCaMP5 neuronal responses to glucoprivation, but not to glutamate. Pharmacologic results suggest that the astrocytic connection with hindbrain CA neurons is purinergic via P2 receptors. Parallel imaging studies on hindbrain slices of NST from wild-type C57BL/6J mice, in which astrocytes and neurons were prelabeled with a calcium reporter dye and an astrocytic vital dye, show that both cell types are activated by glucoprivation but astrocytes responded significantly sooner than neurons. Pretreatment of these hindbrain slices with P2 antagonists abolished neuronal responses to glucoprivation without interruption of astrocyte responses; pretreatment with fluorocitrate eliminated both astrocytic and neuronal responses. These results support earlier work suggesting that the primary detection of glucoprivic signals by the hindbrain is mediated by astrocytes.
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Affiliation(s)
| | | | - Sue Ritter
- 2Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington
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Wagner S, Van Aken O, Elsässer M, Schwarzländer M. Mitochondrial Energy Signaling and Its Role in the Low-Oxygen Stress Response of Plants. PLANT PHYSIOLOGY 2018; 176:1156-1170. [PMID: 29298823 PMCID: PMC5813528 DOI: 10.1104/pp.17.01387] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/29/2017] [Indexed: 05/07/2023]
Abstract
Cellular responses to low-oxygen stress and to respiratory inhibitors share common mitochondrial energy signaling pathways.
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Affiliation(s)
- Stephan Wagner
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, 48143 Münster, Germany
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, 53113 Bonn, Germany
| | | | - Marlene Elsässer
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, 48143 Münster, Germany
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, 53113 Bonn, Germany
- Institute for Cellular and Molecular Botany (IZMB), Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Markus Schwarzländer
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, 48143 Münster, Germany
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, 53113 Bonn, Germany
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TSUNEMITSU A, FOSDICK LS, HUTCHINSON AW. Periodontal Lesions in Hypercitricemia: Effect of Adrenal Cortical Hormones on the Blood Citric Acid Level and the Periodontal Tissues. J Dent Res 2016; 42:87-94. [PMID: 13994601 DOI: 10.1177/00220345630420017201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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SUZUKI T, TSUNEMITSU A, FOSDICK LS. Periodontal Lesions in Hypercitricemia: Effect of Insulin and Some Aconitase-activating Substances on the Blood Citric-Acid Level and the Periodontal Tissues. J Dent Res 2016; 44:309-13. [PMID: 14278185 DOI: 10.1177/00220345650440020201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Rogers RC, Ritter S, Hermann GE. Hindbrain cytoglucopenia-induced increases in systemic blood glucose levels by 2-deoxyglucose depend on intact astrocytes and adenosine release. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1102-8. [PMID: 27101298 PMCID: PMC4935490 DOI: 10.1152/ajpregu.00493.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 04/07/2016] [Indexed: 01/16/2023]
Abstract
The hindbrain contains critical neurocircuitry responsible for generating defensive physiological responses to hypoglycemia. This counter-regulatory response (CRR) is evoked by local hindbrain cytoglucopenia that causes an autonomically mediated increase in blood glucose, feeding behavior, and accelerated digestion; that is, actions that restore glucose homeostasis. Recent reports suggest that CRR may be initially triggered by astrocytes in the hindbrain. The present studies in thiobutabarbital-anesthetized rats show that exposure of the fourth ventricle (4V) to 2-deoxyglucose (2DG; 15 μmol) produced a 35% increase in circulating glucose relative to baseline levels. While the 4V application of the astrocytic signal blocker, fluorocitrate (FC; 5 nmol), alone, had no effect on blood glucose levels, 2DG-induced increases in glucose were blocked by 4V FC. The 4V effect of 2DG to increase glycemia was also blocked by the pretreatment with caffeine (nonselective adenosine antagonist) or a potent adenosine A1 antagonist (8-cyclopentyl-1,3-dipropylxanthine; DPCPX) but not the NMDA antagonist (MK-801). These results suggest that CNS detection of glucopenia is mediated by astrocytes and that astrocytic release of adenosine that occurs after hypoglycemia may cause the activation of downstream neural circuits that drive CRR.
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Affiliation(s)
- Richard C. Rogers
- 1Autonomic Neurosciences Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana; and
| | - Sue Ritter
- 2Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Gerlinda E. Hermann
- 1Autonomic Neurosciences Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana; and
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Weeks AM, Coyle SM, Jinek M, Doudna JA, Chang MCY. Structural and biochemical studies of a fluoroacetyl-CoA-specific thioesterase reveal a molecular basis for fluorine selectivity. Biochemistry 2010; 49:9269-79. [PMID: 20836570 PMCID: PMC3461317 DOI: 10.1021/bi101102u] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We have initiated a broad-based program aimed at understanding the molecular basis of fluorine specificity in enzymatic systems, and in this context, we report crystallographic and biochemical studies on a fluoroacetyl-coenzyme A (CoA) specific thioesterase (FlK) from Streptomyces cattleya. Our data establish that FlK is competent to protect its host from fluoroacetate toxicity in vivo and demonstrate a 10(6)-fold discrimination between fluoroacetyl-CoA (k(cat)/K(M) = 5 × 10⁷ M⁻¹ s⁻¹) and acetyl-CoA (k(cat)/K(M) = 30 M⁻¹ s⁻¹) based on a single fluorine substitution that originates from differences in both substrate reactivity and binding. We show that Thr 42, Glu 50, and His 76 are key catalytic residues and identify several factors that influence substrate selectivity. We propose that FlK minimizes interaction with the thioester carbonyl, leading to selection against acetyl-CoA binding that can be recovered in part by new C═O interactions in the T42S and T42C mutants. We hypothesize that the loss of these interactions is compensated by the entropic driving force for fluorinated substrate binding in a hydrophobic binding pocket created by a lid structure, containing Val 23, Leu 26, Phe 33, and Phe 36, that is not found in other structurally characterized members of this superfamily. We further suggest that water plays a critical role in fluorine specificity based on biochemical and structural studies focused on the unique Phe 36 "gate" residue, which functions to exclude water from the active site. Taken together, the findings from these studies offer molecular insights into organofluorine recognition and design of fluorine-specific enzymes.
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Affiliation(s)
- Amy M. Weeks
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460
| | - Scott M. Coyle
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-1460
| | - Martin Jinek
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-1460
| | - Jennifer A. Doudna
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-1460
| | - Michelle C. Y. Chang
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-1460
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EEG-LARSEN N, NAESS K. The Action of Magnesium and Calcium on Fluoroacetate-Intoxication in Mice. ACTA ACUST UNITED AC 2009; 7:331-6. [PMID: 14894247 DOI: 10.1111/j.1600-0773.1951.tb02874.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Buffa P, Guarriera-Bobyleva V, Pasquali-Ronchetti I. Biochemical effects of fluoroacetate poisoning in rat liver. CIBA FOUNDATION SYMPOSIUM 2008; 2:303-30. [PMID: 5212155 DOI: 10.1002/9780470719855.ch13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Peters R. Some metabolic aspects of fluoroacetate especially related to fluorocitrate. CIBA FOUNDATION SYMPOSIUM 2008; 2:55-76. [PMID: 5212159 DOI: 10.1002/9780470719855.ch4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Abstract
Sodium fluoroacetate was introduced as a rodenticide in the US in 1946. However, its considerable efficacy against target species is offset by comparable toxicity to other mammals and, to a lesser extent, birds and its use as a general rodenticide was therefore severely curtailed by 1990. Currently, sodium fluoroacetate is licensed in the US for use against coyotes, which prey on sheep and goats, and in Australia and New Zealand to kill unwanted introduced species. The extreme toxicity of fluoroacetate to mammals and insects stems from its similarity to acetate, which has a pivotal role in cellular metabolism. Fluoroacetate combines with coenzyme A (CoA-SH) to form fluoroacetyl CoA, which can substitute for acetyl CoA in the tricarboxylic acid cycle and reacts with citrate synthase to produce fluorocitrate, a metabolite of which then binds very tightly to aconitase, thereby halting the cycle. Many of the features of fluoroacetate poisoning are, therefore, largely direct and indirect consequences of impaired oxidative metabolism. Energy production is reduced and intermediates of the tricarboxylic acid cycle subsequent to citrate are depleted. Among these is oxoglutarate, a precursor of glutamate, which is not only an excitatory neurotransmitter in the CNS but is also required for efficient removal of ammonia via the urea cycle. Increased ammonia concentrations may contribute to the incidence of seizures. Glutamate is also required for glutamine synthesis and glutamine depletion has been observed in the brain of fluoroacetate-poisoned rodents. Reduced cellular oxidative metabolism contributes to a lactic acidosis. Inability to oxidise fatty acids via the tricarboxylic acid cycle leads to ketone body accumulation and worsening acidosis. Adenosine triphosphate (ATP) depletion results in inhibition of high energy-consuming reactions such as gluconeogenesis. Fluoroacetate poisoning is associated with citrate accumulation in several tissues, including the brain. Fluoride liberated from fluoroacetate, citrate and fluorocitrate are calcium chelators and there are both animal and clinical data to support hypocalcaemia as a mechanism of fluoroacetate toxicity. However, the available evidence suggests the fluoride component does not contribute. Acute poisoning with sodium fluoroacetate is uncommon. Ingestion is the major route by which poisoning occurs. Nausea, vomiting and abdominal pain are common within 1 hour of ingestion. Sweating, apprehension, confusion and agitation follow. Both supraventricular and ventricular arrhythmias have been reported and nonspecific ST- and T-wave changes are common, the QTc may be prolonged and hypotension may develop. Seizures are the main neurological feature. Coma may persist for several days. Although several possible antidotes have been investigated, they are of unproven value in humans. The immediate, and probably only, management of fluoroacetate poisoning is therefore supportive, including the correction of hypocalcaemia.
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Affiliation(s)
- Alex T Proudfoot
- National Poisons Information Service (Birmingham Centre), City Hospital, Birmingham, UK
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TAYLOR TG, MOORE JH, HERTELENDY F. Variations in the mineral composition of individual bones of the skeleton of the domestic fowl. Br J Nutr 2007; 14:49-57. [PMID: 13837202 DOI: 10.1079/bjn19600009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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CARPENTER FG. THE STABILIZING ACTION OF CARBON DIOXIDE ON PERIPHERAL NERVE FIBERS AND ON THE NEURONS OF THE MEDULLARY RETICULAR FORMATION IN THE RAT*. Ann N Y Acad Sci 2006; 109:480-93. [PMID: 14018819 DOI: 10.1111/j.1749-6632.1963.tb13481.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Goncharov NV, Jenkins RO, Radilov AS. Toxicology of fluoroacetate: a review, with possible directions for therapy research. J Appl Toxicol 2006; 26:148-61. [PMID: 16252258 DOI: 10.1002/jat.1118] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fluoroacetate (FA; CH2FCOOR) is highly toxic towards humans and other mammals through inhibition of the enzyme aconitase in the tricarboxylic acid cycle, caused by 'lethal synthesis' of an isomer of fluorocitrate (FC). FA is found in a range of plant species and their ingestion can cause the death of ruminant animals. Some fluorinated compounds -- used as anticancer agents, narcotic analgesics, pesticides or industrial chemicals -- metabolize to FA as intermediate products. The chemical characteristics of FA and the clinical signs of intoxication warrant the re-evaluation of the toxic danger of FA and renewed efforts in the search for effective therapeutic means. Antidotal therapy for FA intoxication has been aimed at preventing fluorocitrate synthesis and aconitase blockade in mitochondria, and at providing citrate outflow from this organelle. Despite a greatly improved understanding of the biochemical mechanism of FA toxicity, ethanol, if taken immediately after the poisoning, has been the most acceptable antidote for the past six decades. This review deals with the clinical signs and physiological and biochemical mechanisms of FA intoxication to provide an explanation of why, even after decades of investigation, has no effective therapy to FA intoxication been elaborated. An apparent lack of integrated toxicological studies is viewed as a limiter of progress in this regard. Two principal ways of developing effective therapies for FA intoxication are considered. Firstly, competitive inhibition of FA interaction with CoA and of FC interaction with aconitase. Secondly, channeling the alternative metabolic pathways by orienting the fate of citrate via cytosolic aconitase, and by maintaining the flux of reducing equivalents into the TCA cycle via glutamate dehydrogenase.
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Affiliation(s)
- Nikolay V Goncharov
- Research Institute of Hygiene, Occupational Pathology and Human Ecology, Saint-Petersburg, Russia
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LOTSPEICH WD, PETERS RA, WILSON TH. The inhibition of aconitase by 'Inhibitor fractions' isolated from tissues poisoned with fluoroacetate. Biochem J 2004; 51:20-5. [PMID: 14944527 PMCID: PMC1197782 DOI: 10.1042/bj0510020] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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AZOUZ WM, PARKE DV, WILLIAMS RT. Studies in detoxication, 42. Fluorobenzene: Spectrophotometric determination of the elimination of unchanged halogenobenzenes by rabbits; a comparison of the oxidation in vivo of fluorobenzene and of benzene. Biochem J 2004; 50:702-6. [PMID: 14934677 PMCID: PMC1197730 DOI: 10.1042/bj0500702] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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BUFFA P, PETERS RA, WAKELIN RW. Biochemistry of fluoroacetate poisoning; isolation of an active tricarboxylic acid fraction from poisoned kidney homogenates. Biochem J 2004; 48:467-77. [PMID: 14838868 PMCID: PMC1275352 DOI: 10.1042/bj0480467] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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ACKERMANN WW. The relation of the Krebs cycle to viral synthesis. II. The effect of sodium fluoroacetate on the propagation of influenza virus in mice. ACTA ACUST UNITED AC 2004; 93:635-42. [PMID: 14832407 PMCID: PMC2136068 DOI: 10.1084/jem.93.6.635] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A further study has been made of the relationship of reactions of the Krebs cycle to the propagation of influenza virus. By the administration of sublethal doses of sodium fluoroacetate which were found to increase the concentration of citrate in the mouse lung, it was possible to demonstrate a blocking of the citric acid cycle in that organ. Further, the intraperitoneal administration of these concentrations of fluoroacetate was found to inhibit markedly the propagation of influenza, Type A, virus in the lungs of mice. The inhibition was observed when the fluoroacetate was administered 15 minutes, 6 hours, or 12 hours after the mice were inoculated with virus. This effect was also demonstrable when the concentration of the viral inoculum was varied over a range of virus titers from 103.5 to 106.5. Sodium fluoroacetate was found to have no effect in vitro on the infectivity or hemagglutinating property of the virus. The significance of these findings with regard to chemotherapy and to the mechanism of viral synthesis is described.
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Hanson ML, Sibley PK, Mabury SA, Muir DCG, Solomon KR. Field level evaluation and risk assessment of the toxicity of dichloroacetic acid to the aquatic macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2003; 55:46-63. [PMID: 12706393 DOI: 10.1016/s0147-6513(02)00094-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Dichloroacetic acid (DCA), a haloacetic acid, is a common contaminant of aquatic ecosystems. A study to investigate potential phytotoxic effects on rooted and floating macrophytes (Myriophyllum spicatum, M. sibiricum, and Lemna gibba) was conducted. Replicate 12,000 L outdoor microcosms (n = 3) were treated with 3, 10, 30, and 100 mg/L of DCA that had been neutralized to the sodium salt, plus controls. Plants were sampled regularly over 21 days and assessed for a variety of endpoints including plant growth, root growth, number of nodes, wet and dry mass, chlorophyll-a, chlorophyll-b, carotenoids, and citrate levels. EC10, EC25, and EC50 values were calculated for each endpoint that exhibited a concentration-response. Overall, M. sibiricum was slightly more sensitive than M. spicatum to DCA exposure. The most sensitive plant endpoints were wet mass and plant length. Pigments showed no response with exposure to DCA. The probability of current concentrations of DCA in Canadian lake water and Swiss river waters exceeding thresholds of toxicity derived from single species effect measure distributions (EC10s) is << 0.01%. The use of effect measure distributions holds promise as a new risk assessment technique for aquatic plants. Currently, environmental levels of DCA do not pose a risk to these plants.
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Affiliation(s)
- Mark L Hanson
- Department of Environmental Biology, Centre for Toxicology, University of Guelph, Ont., N1G 2W1, Guelph, Canada
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Hanson ML, Sibley PK, Ellis DA, Mabury SA, Muir DCG, Solomon KR. Evaluation of monochloroacetic acid (MCA) degradation and toxicity to Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum in aquatic microcosms. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2002; 61:251-273. [PMID: 12359395 DOI: 10.1016/s0166-445x(02)00089-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The fate of monochloroacetic acid (MCA), a common phytotoxic aquatic contaminant, and its toxicity to the aquatic macrophytes Lemna gibba (L. gibba), Myriophyllum spicatum (M. spicatum), and Myriophyllum sibiricum (M. sibiricum) under semi-natural field conditions was studied. Replicate 12,000 l enclosures were treated with 0, 3, 10, 30 and 100 mg/l of MCA. Each microcosm was stocked with eight individual apical shoots of M. spicatum and M. sibiricum 1 day prior to initiation of exposure. Plants were sampled after 4, 7, 14 and 28 days of exposure and their response assessed using numerous somatic and biochemical endpoints. L. gibba was introduced into the microcosms the day of MCA treatment and monitored regularly for 21 days. The half-life of MCA in the water column ranged between 86 and 523 h. The most sensitive plant species was M. spicatum, followed by M. sibiricum and L. gibba. All species demonstrated toxicity within a threefold range of each other. Endpoint sensitivity varied depending on the duration of exposure and the level of effect chosen. Most species endpoint EC(x) values were less than an order of magnitude different. Citrate levels in Myriophyllum spp. were not influenced by exposure to MCA. The toxicity of MCA to M. spicatum and M. sibiricum was very similar and thus highly predictive of toxicity observed for each other. The EC(10) was a more conservative estimate of toxicity than the statistically derived no observed effect concentration. Current concentrations of MCA are not likely to pose a risk to these aquatic plants in surface waters.
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Affiliation(s)
- Mark L Hanson
- Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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LIEBECQ C, LIEBECQ-HUTTER S. [Effect of fluoroacetates & x-rays on the citric acid content of the liver in mice]. ACTA ACUST UNITED AC 2000; 14:216-7. [PMID: 13562065 DOI: 10.1007/bf02159096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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PETERS RA, WAKELIN RW, MARTIN AJ, WEBB J, BIRKS FT. Observations upon the toxic principle in the seeds of Dichapetalum toxicarium; separation of a long-chain fatty acid containing fluorine. Biochem J 2000; 71:245-8. [PMID: 13628562 PMCID: PMC1196782 DOI: 10.1042/bj0710245] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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CRAWFORD MA, MILNE MD, SCRIBNER BH. The effects of changes in acid-base balance on urinary citrate in the rat. J Physiol 1998; 149:413-23. [PMID: 13812721 PMCID: PMC1363098 DOI: 10.1113/jphysiol.1959.sp006348] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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WILLIAMSON J. Drug resistance in trypanosomes: effects of metabolic inhibitiors, pH and oxidation-reduction potential on normal and resistant Trypanosoma rhodesiense. BRITISH JOURNAL OF PHARMACOLOGY AND CHEMOTHERAPY 1998; 14:443-55. [PMID: 13844959 PMCID: PMC1481899 DOI: 10.1111/j.1476-5381.1959.tb00948.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A wide variety of metabolic inhibitors tested in vitro for trypanocidal activity on normal and drug-resistant strains of Trypanosoma rhodesiense showed no relation between acquired drug resistance and changes in specific enzymatic function. Oxidation-reduction potential is an important factor in trypanocidal action but is not obviously related to the development of resistance. The dependence on pH of the trypanocidal action of ionizing drugs against both normal and resistant trypanosomes supports the postulate that the development of resistance involves physical changes in cell structures associated with the uptake of drug.
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PUCCI I. MITOCHONDRIAL CHANGES INDUCED BY FLUOROACETATE IN CHICK EMBRYO MYOCARDIUM IN VIVO. Exp Cell Res 1996; 35:412-4. [PMID: 14195448 DOI: 10.1016/0014-4827(64)90107-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Beinert H, Kennedy MC, Stout CD. Aconitase as Ironminus signSulfur Protein, Enzyme, and Iron-Regulatory Protein. Chem Rev 1996; 96:2335-2374. [PMID: 11848830 DOI: 10.1021/cr950040z] [Citation(s) in RCA: 418] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Helmut Beinert
- Institute for Enzyme Research, Graduate School, and Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison, Wisconsin 53705, Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
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Park BK, Kitteringham NR. Effects of fluorine substitution on drug metabolism: pharmacological and toxicological implications. Drug Metab Rev 1994; 26:605-43. [PMID: 7924905 DOI: 10.3109/03602539408998319] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- B K Park
- Department of Pharmacology and Therapeutics, University of Liverpool, England
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Hornfeldt CS, Larson AA. Seizures induced by fluoroacetic acid and fluorocitric acid may involve chelation of divalent cations in the spinal cord. Eur J Pharmacol 1990; 179:307-13. [PMID: 2364992 DOI: 10.1016/0014-2999(90)90170-b] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fluoroacetic and fluorocitric acid toxicity is often characterized by seizures, however the mechanism of this activity is unknown. Intrathecal (i.t.) injection of fluorocitrate in mice resulted in seizures after an average latency of 15 s, while intracerebroventricular (i.c.v.) injection produced seizures after 36.5 min, and required higher doses to achieve this effect. This indicates the probable site of fluoroacetate and fluorocitrate neurotoxicity is the spinal cord. To mimic citrate accumulation, characteristic of fluoroacetate and fluorocitrate poisoning, citric acid was injected i.t. and also found to produce seizures. The structurally unrelated compounds EDTA, EGTA, glutamic acid and lactic acid also produced seizures identical to fluorocitrate. The ability of these compounds to chelate Ca2+ correlates well with their ability to cause seizures when administered i.t. and coadministration of calcium greatly attenuated the neurotoxicity of these compounds as well as fluoroacetate and fluorocitrate. In contrast, Ca2+ was unable to inhibit seizures elicited by strychnine, suggesting calcium's ability to inhibit chelators of divalent cations is not due to a general anticonvulsant effect. These results suggest that changes in Ca2+ concentration in the spinal cord may be responsible for some forms of seizure activity.
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Affiliation(s)
- C S Hornfeldt
- Department of Veterinary Biology, University of Minnesota, St. Paul, MN 55108
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Liébecq C. Commentary on 'The Toxicity of Fluoroacetate and the Tricarboxylic Acid Cycle'. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 1000:251-3. [PMID: 2673372 DOI: 10.1016/s0006-3002(89)80021-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Bosakowski T, Levin AA. Comparative acute toxicity of chlorocitrate and fluorocitrate in dogs. Toxicol Appl Pharmacol 1987; 89:97-104. [PMID: 3590193 DOI: 10.1016/0041-008x(87)90180-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The high-dose effects of chlorocitrate [(-)-threo-chlorocitric acid] were compared in vivo to another halogenated citrate analog, and a well-known inhibitor of the tricarboxylic acid (TCA) cycle, fluorocitrate. The compounds were given iv to two dogs per sex per group, and a control group received an equimolar amount of citric acid. Chlorocitrate (100 mg/kg) showed TCA cycle inhibition as did fluorocitrate (8 mg/kg) in that both caused depletion of ATP and accumulation of citrate in the liver. Chlorocitrate was a significantly weaker inhibitor of citrate metabolism than fluorocitrate as evidenced by a substantially lower accumulation of serum citrate despite a much higher dose. Both halocitrates produced a similar diabetes-like syndrome (hyperglycemia, glycosuria) mediated by a significant hyperglucagonemia and slight hypoinsulinemia. Chlorocitrate was more potent in this effect and a much greater buildup of plasma lactate ensued (18- versus 3.7-fold increase), enough to explain lethality observed in earlier studies. In contrast, fluorocitrate produced a severe life-threatening hypocalcemia (-30%), and hypercalcuria was observed. This effect on calcium distribution was only minimal with chlorocitrate. Both halocitrates had a similar depressive effect on circulation as evidenced by hypothermia, bradycardia, and elongation of the QT-interval. These changes were considered to be the result of lactic acidosis and the ongoing ion imbalance since heart ATP levels were not depleted.
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Bosakowski T, Levin AA. Serum citrate as a peripheral indicator of fluoroacetate and fluorocitrate toxicity in rats and dogs. Toxicol Appl Pharmacol 1986; 85:428-36. [PMID: 3764925 DOI: 10.1016/0041-008x(86)90350-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The utility of serum citrate as a peripheral indicator of toxicity was tested as a possible investigational probe for compounds which inhibit citrate metabolism. Fluoroacetate (FA) and its putative toxic metabolite, fluorocitrate (FC), were given to rats and dogs in a series of studies. In rats, 3 mg/kg FA (po) caused a 46% depletion in heart ATP concentrations and a 15-fold increase in heart citrate concentrations. Both of these changes were significantly correlated with a fivefold elevation in serum citrate. In dogs, citrate accumulation was less pronounced (two-to threefold) in the heart and serum, and heart ATP concentrations were not significantly reduced. However, the time course of serum citrate elevations corresponded with the appearance of serious clinical signs and death. In range-finding studies with rats or dogs, serum citrate elevations were always observed in a dose-related pattern according to the dose of FA or FC administered. In contrast to FA, toxic doses of FC did not reduce heart ATP in either rats or dogs, and heart citrate accumulation was less marked than with FA. Both FA and FC produced significant hyperglycemia (twofold increase) in both rats and dogs and high correlations were established between serum glucose and serum citrate in both species. Serum total calcium was reduced (-18%) in dogs treated with FC (8 mg/kg, iv) and a strong inverse correlation to serum citrate was shown. This correlation is biologically meaningful in light of the known chelating effect of citrate on calcium. Clinical manifestations of tremors, tetany, and convulsions in FC-treated dogs were consistent with known symptoms of hypocalcemia. No decrease in total calcium was observed in rats treated with either FA or FC. Despite certain species differences in response to the two fluoro inhibitors, serum citrate levels were always reflective of nontoxic, toxic, or lethal doses.
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Taitelman U, Roy A, Hoffer E. Fluoroacetamide poisoning in man: the role of ionized calcium. ARCHIVES OF TOXICOLOGY. SUPPLEMENT. = ARCHIV FUR TOXIKOLOGIE. SUPPLEMENT 1983; 6:228-31. [PMID: 6578726 DOI: 10.1007/978-3-642-69083-9_41] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Two cases are reported of severe acute fluoroacetamide poisoning in man, with successful treatment of the life-threatening cardiac arrhythmias by the administration of calcium chloride. The arrhythmias were preceded by prolongation of the QT interval in the ECG. Calcium chloride therapy restored to normal the markedly prolonged QT interval.
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Taitelman U, Roy A, Raikhlin-Eisenkraft B, Hoffer E. The effect of monoacetin and calcium chloride on acid-base balance and survival in experimental sodium fluoroacetate poisoning. ARCHIVES OF TOXICOLOGY. SUPPLEMENT. = ARCHIV FUR TOXIKOLOGIE. SUPPLEMENT 1983; 6:222-7. [PMID: 6578725 DOI: 10.1007/978-3-642-69083-9_40] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Sodium fluoroacetate (compound "1080") was injected intravenously, 3 mmol/kg, to artificially-ventilated anesthetized cats. Blood pressure, ECG, acid-base parameters and serum ionized calcium were monitored in four groups of cats. Group A served as control. Group B cats were treated with calcium chloride to restore normal values of serum ionized calcium. Group C was given monoacetin (glyceryl monoacetate), 0.5 ml/kg every 30 min. Both monoacetin and calcium chloride were given to cats in group D. Fluoroacetate poisoning caused significant decrease in ionized calcium and severe metabolic acidosis with increased levels of lactate and pyruvate. The lactate to pyruvate ratio remained normal as long as there was no significant drop in blood pressure. Correction of blood ionized calcium prolonged survival from 94 to 166 min (group B). Monoacetin prolonged average survival time to 166 min. Metabolic acidosis was aggravated in monoacetin-treated animals (group C). Combined treatment with monoacetin and calcium chloride did not prolong mean survival time above 166 min.
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Abstract
A comparison was made of the major excretory products when adult Haemonchus contortus worms were incubated with D-[U-14C]glucose under aerobic and anaerobic conditions. Catabolites measured were propan-1-ol, acetate, n-propionate and CO2 and the only major difference was that nearly twice as much CO2 both in terms of quantity and radioactivity was excreted under aerobic than anaerobic conditions. The worms were also much more physically active under aerobic conditions. When worms were incubated under aerobic conditions with increasing amounts of fluoroacetate their CO2 production was progressively reduced to the anaerobic level. Their movement and their ability to clump together was also progressively reduced. After aerobic incubation with fluoroacetate and D-[U-14C]glucose the quantity and radioactivity of citrate within worms increased greatly. When worms were similarly incubated anaerobically no increase in citrate occurred, no radioactivity was associated with the citrate and the worms appeared physically unaffected. When worms were incubated aerobically with fluoro[1(-14)C]acetate they produced radioactive fluorocitrate.
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Korth M, Weger N, Reiter M. The positive inotropic action of sodium fluoroacetate on guinea-pig ventricular myocardium. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1978; 303:7-14. [PMID: 673016 DOI: 10.1007/bf00496180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Kostyniak PJ, Bosmann HB, Smith FA. Defluorination of fluoroacetate in vitro by rat liver subcellular fractions. Toxicol Appl Pharmacol 1978; 44:89-97. [PMID: 27881 DOI: 10.1016/0041-008x(78)90287-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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D'Onofrio C, Paradisi F, Piccolo D. The influence of some metabolic inhibitors on in vitro phagocytizing macrophages. I. The behaviour of human macrophages. Med Microbiol Immunol 1977; 163:195-207. [PMID: 916975 DOI: 10.1007/bf02126678] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the present work the uptake of foreign materials by macrophages has been studied in order to elucidate its possible energy-dependent mechanisms. We used monolayer cultures of macrophages from human peripheral venous blood, treated with the following metabolic inhibitors: iodoacetic acid, fluoroacetic acid, sodium fluoride, sodium malonate, sodium azide, 2-4-dinitrophenol, cycloheximide, and ouabain. The test assay was performed by using a zymosan particles suspension in Mc Coy 5 A medium supplemented as follows. The quantitation of phagocytosis was obtained by direct count of intracellular zymosan particles by oil 100X microscopy and the results were submitted to a statistical evaluation. The most effective inhibitor we found was iodoacetate, an inhibitor of anaerobic glycolysis, but fluoride, which acts on the same metabolic pathway at a different site, was quite ineffective. The same ineffectiveness we found for fluoracetate and malonate which act on the Krebs cycle. On the contrary, dinitrophenol (uncoupler of oxidative phosphorylation), azide (inhibitor of cytochrome linked-phosphorylation), ouabain (inhibitor of membrane ATPase activity) and cycloheximide (inhibitor of protein synthesis) give a remarkable decrease of index of phagocytosis after a 3h incubation. In conclusion, we can suppose that the energy-dependent phagocytosis is first depending on transport across the cell membrane (ATPase activity and protein synthesis) and second both on anaerobic glycolysis and oxidative phosphorylation.
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Buffa P, Pasquali-Ronchetti I. Biochemical lesions of respiratory enzymes and configurational changes of mitochondria in vivo. II. Early ultrastructural modifications correlated to the biochemical lesion induced by fluoroacetate. Cell Tissue Res 1977; 183:1-23. [PMID: 922823 DOI: 10.1007/bf00219988] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Correlative biochemical and electron microscopic alterations were observed in chick embryo myoblasts in vitro after treatment with fluoroacetate. Fluoroacetate poisoning caused an increase of citrate and a decrease of ATP in the cultures. Cell respiration was only slighly impaired by fluoroacetate in the first 10 min but was inhibited to 30% one hour after exposure to the poison. Fluoroacetate did not affect oxidative phosphorylation. The evidence suggests that fluoroacetate was transformed in myoblasts into fluorocitrate which inhibited the mitochondrial-bound aconitate hydratase as in adult tissues. Ultrastructural changes in the majority of the fluoroacetate-treated cells were observed. Very few myoblasts appeared unaffected by the poison. Mitochondria were specifically altered. The early changes occurred in the mitochondrial matrix where the inhibited enzyme is known to be located and were followed by modifications in the configuration and structure of cristae. Exogenous fluorocitrate caused ultrastructural changes in the mitochondria similar to that provoked by fluoroacetate. The localization of the early change in the mitochondrial matrix and the evaluation of the structural modifications suggest a correlation between the biochemical lesion, i.e. the inhibition of aconitate hydratase, and the change revealed in the mitochondrial structure containing the inhibited enzyme.
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Godoy HM, del Carmen Villarruel M. Myocardial adenine nucleotides, hexose phosphates and inorganic phosphate, and the regulation of phosphofructokinase activity during fluoroacetate poisoning in the rat. Biochem Pharmacol 1974; 23:3179-89. [PMID: 4155303 DOI: 10.1016/0006-2952(74)90604-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Johannsen FR, Knowles CO. Toxicity and action of fluenethyl acaricide and related compounds in the mouse, housefly and twospotted spider mite. COMPARATIVE AND GENERAL PHARMACOLOGY 1974; 5:101-10. [PMID: 4459027 DOI: 10.1016/s0306-3623(74)80014-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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