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Del Pino J, Moyano P, Ruiz M, Anadón MJ, Díaz MJ, García JM, Labajo-González E, Frejo MT. Amitraz changes NE, DA and 5-HT biosynthesis and metabolism mediated by alterations in estradiol content in CNS of male rats. CHEMOSPHERE 2017; 181:518-529. [PMID: 28463726 DOI: 10.1016/j.chemosphere.2017.04.113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 04/20/2017] [Accepted: 04/23/2017] [Indexed: 05/21/2023]
Abstract
Amitraz is a formamidine insecticide/acaricide that alters different neurotransmitters levels, among other neurotoxic effects. Oral amitraz exposure (20, 50 and 80 mg/kg bw, 5 days) has been reported to increase serotonin (5-HT), norepinephrine (NE) and dopamine (DA) content and to decrease their metabolites and turnover rates in the male rat brain, particularly in the striatum, prefrontal cortex, and hippocampus. However, the mechanisms by which these alterations are produced are not completely understood. One possibility is that amitraz monoamine oxidase (MAO) inhibition could mediate these effects. Alternatively, it alters serum concentrations of sex steroids that regulate the enzymes responsible for these neurotransmitters synthesis and metabolism. Thus, alterations in sex steroids in the brain could also mediate the observed effects. To test these hypothesis regarding possible mechanisms, we treated male rats with 20, 50 and 80 mg/kg bw for 5 days and then isolated tissue from striatum, prefrontal cortex, and hippocampus. We then measured tissue levels of expression and/or activity of MAO, catechol-O-metyltransferase (COMT), dopamine-β-hydroxylase (DBH), tyrosine hydroxylase (TH) and tryptophan hydroxylase (TRH) as well as estradiol levels in these regions. Our results show that amitraz did not inhibit MAO activity at these doses, but altered MAO, COMT, DBH, TH and TRH gene expression, as well as TH and TRH activity and estradiol levels. The alteration of these enzymes was partially mediated by dysregulation of estradiol levels. Our present results provide new understanding of the mechanisms contributing to the harmful effects of amitraz.
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Affiliation(s)
- Javier Del Pino
- Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain.
| | - Paula Moyano
- Department of Toxicology and Legal Medicine, Medical School, Complutense University of Madrid, 28041 Madrid, Spain
| | - Matilde Ruiz
- Department of Toxicology and Legal Medicine, Medical School, Complutense University of Madrid, 28041 Madrid, Spain
| | - María José Anadón
- Department of Toxicology and Legal Medicine, Medical School, Complutense University of Madrid, 28041 Madrid, Spain
| | - María Jesús Díaz
- Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain
| | - José Manuel García
- Department of Toxicology and Legal Medicine, Medical School, Complutense University of Madrid, 28041 Madrid, Spain
| | - Elena Labajo-González
- Department of Toxicology and Legal Medicine, Medical School, Complutense University of Madrid, 28041 Madrid, Spain
| | - María Teresa Frejo
- Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain
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Institoris L, Banfi H, Lengyel Z, Papp A, Nagymajtenyi L. A study on immunotoxicological effects of subacute amitraz exposure in rats. Hum Exp Toxicol 2016; 26:441-5. [PMID: 17623769 DOI: 10.1177/0960327107076887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effects of amitraz, a formamidine pesticide, were investigated in four-week old outbred male Wistar rats on certain classic toxicological and haematological parameters as well as on specific immune functions. The animals were treated, per os by gavage for 28 days, in a five-day treatment two days break system, with 26.5, 21.1, 10.6 and 5.29 mg/kg/day amitraz. On the 29th day, organ weights of the thymus, heart, lung, spleen, liver, kidneys, adrenals, testicles and popliteal lymph node; WBC and RBC counts, Ht, MCV, haemoglobin; and cell content of the femoral bone marrow were determined. In two separate groups, the effects of amitraz on the PFC content of the spleen, and on the maximum level and time course of DTH reaction, were investigated. Amitraz in 26.5 mg/kg dose increased relative adrenal weight, and decreased relative liver weight, MCV value, PFC content of the spleen, and the maximum level of DTH reaction. The 21.1 mg/kg dose decreased only MCV value, while 10.6 mg/kg elevated the liver-to-brain weight ratio. Based of these findings, a NOEL dose of 5.29 mg/kg was determined for amitraz in this experimental system; while the LOEL doses were 10.6 mg/kg for the general toxicological, 21.1 mg/kg for the haematological and 26.5 mg/kg for the immune function parameters. The results show that the exposure sensitivity of these immune functions to amitraz is lower than that of some other toxicological and haematological parameters. Human & Experimental Toxicology ( 2007) 26 , 441—445
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Affiliation(s)
- L Institoris
- Department of Public Health, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
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del Pino J, Moyano-Cires PV, Anadon MJ, Díaz MJ, Lobo M, Capo MA, Frejo MT. Molecular Mechanisms of Amitraz Mammalian Toxicity: A Comprehensive Review of Existing Data. Chem Res Toxicol 2015; 28:1073-94. [DOI: 10.1021/tx500534x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Javier del Pino
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
| | - Paula Viviana Moyano-Cires
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
| | - Maria Jose Anadon
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
| | - María Jesús Díaz
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
| | - Margarita Lobo
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
| | - Miguel Andrés Capo
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
| | - María Teresa Frejo
- Departament of Toxicology
and Pharmacology, Veterinary School, and ‡Department of
Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain
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Del Pino J, Martínez M, Castellano V, Ramos E, Martínez-Larrañaga M, Anadón A. Effects of exposure to amitraz on noradrenaline, serotonin and dopamine levels in brain regions of 30 and 60 days old male rats. Toxicology 2013; 308:88-95. [PMID: 23541472 DOI: 10.1016/j.tox.2013.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 02/27/2013] [Accepted: 03/19/2013] [Indexed: 10/27/2022]
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5
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Crofton KM, Boncek VM, Reiter LW. Acute effects of amitraz on the acoustic startle response and motor activity. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780270102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bushnell PJ. Advanced Behavioral Testing in Rodents: Assessment of Cognitive Function in Animals. ACTA ACUST UNITED AC 1999; Chapter 11:Unit11.4. [DOI: 10.1002/0471140856.tx1104s00] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Philip J. Bushnell
- National Health and Environmental Effects Research Laboratory, U.S. Environment Protection Agency Research Triangle Park North Carolina
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Berman E, House DE, Allis JW, Simmons JE. Hepatotoxic interactions of ethanol with allyl alcohol or carbon tetrachloride in rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1992; 37:161-76. [PMID: 1522609 DOI: 10.1080/15287399209531663] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To assess whether potential toxic interactions occur between ethanol and allyl alcohol or carbon tetrachloride following subacute, concurrent chemical exposure, male Fischer 344 rats, approximately 70 d of age, were given ethanol at 0, 0.05, 0.1, 0.2, or 0.5 ml/kg in corn oil daily by gavage for 14 d (ETOH group), or the same levels of ethanol with 21 mg allyl alcohol/kg (ALAC group), or the same levels of ethanol with 20 mg carbon tetrachloride/kg (CCL4 group). Hepatic response was assessed 24 h after the last dose. Interactions were evaluated by comparing the ETOH group with either the ALAC group or the CCL4 group using multivariate analysis of variance procedures. No statistically significant interaction was seen between the ETOH group and the ALAC group at the dosages used. Although an interaction between ethanol and carbon tetrachloride given simultaneously was not statistically significant, a small interactive effect on weight gain from d 0 to termination was apparent (p = .057). Exposure to ethanol alone resulted in a concentration-dependent decrease in absolute and relative liver weight, with a threshold between 0.05 and 0.1 ml/kg. There was no histopathological evidence of hepatic damage with ethanol alone, and no effect on hepatic cytochrome P-450 and glutathione levels or on serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALK). Exposure to allyl alcohol alone resulted in significant increases in absolute and relative liver weights, liver glutathione, and periportal hepatocellular vacuolar degeneration. Exposure to carbon tetrachloride alone resulted in significant increases in absolute and relative liver weight, serum levels of ALT, AST, and ALK, and centrilobular hepatocellular vacuolar degeneration and necrosis. These observations indicate that subacute, concurrent exposure of ethanol with carbon tetrachloride or allyl alcohol at ethanol levels comparable to those reported in gavage vehicles did not result in interactive toxicity.
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Affiliation(s)
- E Berman
- Developmental Toxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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8
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Moser VC, McDaniel KL, Phillips PM. Rat strain and stock comparisons using a functional observational battery: baseline values and effects of amitraz. Toxicol Appl Pharmacol 1991; 108:267-83. [PMID: 2017756 DOI: 10.1016/0041-008x(91)90117-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A functional observational battery (FOB) was utilized to assess the effects of 3-day exposure to the formamidine pesticide amitraz in outbred Sprague-Dawley-derived and inbred Fischer-344-derived (F344) rats (both from Charles River Laboratories) and in outbred Long-Evans rats obtained from two commercial suppliers (Charles River Breeding Laboratories and Blue Spruce Farms). Significant strain and stock differences were obtained in baseline values for one-third of the FOB measures. In most cases, F344 rats were different from the others. Characteristic signs of amitraz exposure consisting of increased excitability, hyper-reactivity, and physiological and autonomic changes were evident in all treated rats. These effects increased with repeated dosing, and many were still present 6 days after dosing. On individual measures, there were differences between the strains and stocks in terms of sensitivity and time course of amitraz effects. In general, Blue Spruce Long-Evans rats displayed more effects of amitraz and F344 rats recovered more quickly than others. Although Sprague-Dawley rats showed the least effect overall, they displayed the largest increases in the sensorimotor responses to stimuli. These data indicate that although some behavioral and physiological parameters showed strain and supplier differences, in both baseline values and the effects of amitraz, conclusions concerning its neurotoxic potential in a screening context would be similar.
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Affiliation(s)
- V C Moser
- NSI Technology Services, Inc., Research Triangle Park, North Carolina 27709
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Costa LG, Wu DS, Olibet G, Murphy SD. Formamidine pesticides and alpha 2-adrenoceptors: studies with amitraz and chlordimeform in rats and development of a radioreceptor binding assay. Neurotoxicol Teratol 1989; 11:405-11. [PMID: 2552275 DOI: 10.1016/0892-0362(89)90014-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The interaction of the formamidine pesticides chlordimeform (CDM) and amitraz (AMZ) with rat brain alpha2-adrenoceptors was investigated. Both compounds inhibited the binding of 3H-clonidine and 3H-yohimbine in vitro with IC50 values of 62-68 microM (CDM) and 95-110 nM (AMZ). In vivo administration of AMZ and CDM caused a dose-dependent inhibition of 3H-clonidine binding in rat forebrain. The inhibition was short-lasting (24 hr) following CDM administration, while after AMZ recovery of 3H-clonidine binding occurred only after 72 hr. Good correlations were found between inhibition of brain 3H-clonidine binding by the formamidines and "plasma equivalents" of these compounds and/or their biologically active metabolites, as measured by a new radioreceptor assay. These results suggest that 1) formamidines can interact in vivo with brain alpha 2-adrenoceptors when administered at doses previously shown to cause toxic effects on the central nervous system: and 2) this effect is reversible, both in vivo and in vitro, and appears to be linked to the presence of the formamidines and/or their active metabolites at the receptor sites.
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Affiliation(s)
- L G Costa
- Department of Environmental Health, University of Washington, Seattle 98195
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Abstract
The present study characterized the effect of the formamidine pesticide, amitraz, upon hippocampal function in male Long-Evans rats. Animals were chronically prepared with a stimulating electrode in the perforant path and field potentials were recorded from a bipolar electrode situated across the granule cell layer of the dentate gyrus. Input/output functions and paired pulse inhibition were monitored in unrestrained, unanesthetized animals over a number of days following acute administration of 100 mg/kg of amitraz. Input/output functions revealed a decrease in excitatory postsynaptic potential (ESP) slope and an increase in population spike height 4 and 24 hr after treatment, with return to baseline by 48 hr. Tests of inhibition using pairs of stimulus pulses delivered at intervals ranging between 20 and 100 msec revealed a decrease in inhibition following amitraz. Both of these effects could be mimicked by administration of 0.1 mg/kg of the alpha-2 agonist clonidine, supporting this mode of action of amitraz on CNS function. These results indicate that systemic amitraz treatment produced a transient enhancement of excitatory and reduction of inhibitory processes in a CNS pathway.
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Affiliation(s)
- M E Gilbert
- Northrop Services Inc., Research Triangle Park, NC 27709
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