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Tengho Toguem SM, Malik I, Hussain M, Iqbal J, Villinger A, Langer P. Synthesis of functionalized benzothiophenes and dibenzothiophenes by twofold Heck and subsequent 6π-electrocyclization reactions of 2,3-dibromothiophenes and 2,3-dibromobenzothiophenes. Tetrahedron 2013. [DOI: 10.1016/j.tet.2012.10.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Diels–Alder reactions for the rational design of benzo[b]thiophenes: DFT-based guidelines for synthetic chemists. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2011.11.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Paul N, Muthusubramanian S. Domino Vilsmeier–Haack/ring closure sequences: a facile synthesis of 3-chlorobenzo[b]thiophene-2-carbaldehydes. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.05.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Synthesis of functionalized benzothiophenes by twofold Heck and subsequent 6π-electrocyclization reactions of 2,3-dibromothiophene. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.06.057] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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David M, Patil VK, Chebbi SG, Marigoudar SR, Chittaragi JB, Halappa R. Gas-liquid chromatography for fenvalerate residue analysis: In vivo alterations in the acetylcholinesterase activity and acetylcholine in different tissues of the fish,Labeo rohita(Hamilton). Toxicol Mech Methods 2009; 19:410-5. [DOI: 10.1080/15376510903089565] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Mushigeri SB, David M. Fenvalerate induced changes in the Ach and associated AchE activity in different tissues of fish Cirrhinus mrigala (Hamilton) under lethal and sub-lethal exposure period. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 20:65-72. [PMID: 21783569 DOI: 10.1016/j.etap.2004.10.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 10/19/2004] [Indexed: 05/31/2023]
Abstract
The disruption of acetylcholinesterase activity in freshwater fish Cirrhinus mrigala (Hamilton) is demonstrated in the present study using acetylcholine chloride as substrate. Fish, C. mrigala on exposure to lethal and sub-lethal concentration of synthetic pyrethroid insecticide, fenvalerate showed inhibition in the activity of the AchE suggesting decrease in the cholinergic transmission and consequent accumulation of Ach in the tissues, namely, gill, muscle, liver and brain. This might have lead to behavioural changes and create widespread disturbance in the normal physiology, ultimately causing the death of the fish. Residue analysis using gas-liquid chromatography technique (GLC) revealed that highest quantity of fenvalerate accumulated in gill followed by liver and muscle under lethal concentration, whereas in sub-lethal concentration muscle accumulated highest concentration followed by gill and liver. The results suggest that in biomonitoring programme, AchE can be a good diagnostic tool for fenvalerate toxicity.
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Affiliation(s)
- S B Mushigeri
- Department of Zoology, Toxicology Division, Karnatak Science College, Dharwad, Karnataka 580001, India
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Tiwari S, Singh A. Piscicidal and anti-acetylcholinesterase activity of Euphorbia royleana stem bark extracts against freshwater common predatory fish Channa punctatus. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2004; 18:47-53. [PMID: 21782734 DOI: 10.1016/j.etap.2004.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Accepted: 05/09/2004] [Indexed: 05/31/2023]
Abstract
The present paper deals with the piscicidal activity of different solvent extracts of Euphorbia royleana stem bark against freshwater predatory fish Channa punctatus, which is commonly present in shrimp and carp culture ponds. The rank of order of toxicity of different solvent extract was: diethyl ether (LC(50) (96h) 31.76mg DW/L) > chloroform (LC(50) (96h) 56.26mg DW/L) > methanol (LC(50) (96h) 56.80mg DW/L) > acetone (LC(50) (96h) 65.77mg DW/L). There was a significant (P < 0.05) negative correlation between LC values and exposure periods, thus increase in exposure time. The LC(50) values of diethyl ether extract of E. royleana stem bark decrease from 81.78mg DW/L (24h) to 31.76mg DW/L (96h). Similar trend were also observed in case of chloroform, methanol and acetone extracts. Exposure of sub-lethal doses (40% and 80% of LC(50)) of the diethyl ether extract for 24h or 96h caused significant inhibition in the activity of enzyme acetylcholinesterase (AChE) in liver and muscle tissue of fish C. punctatus. There was a significant recovery observed in the activity of enzyme acetylcholinesterase in both the tissues of fish after 7th day of the withdrawal of treatment. Thus, the diethyl ether extract of E. royleana stem bark can be used for control of unwanted predatory fish C. punctatus from fish culture ponds. Their toxicological action is due to their anti-acetylcholinesterase enzyme activity, reversibility in their action is advantageous factor for their use as environmentally safe piscicide in aquatic bodies.
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Affiliation(s)
- Sudhanshu Tiwari
- Natural Product Laboratory, Department of Zoology, D.D.U. Gorakhpur University, Gorakhpur 273 009, U.P., India
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Abdel-Rahman A, Dechkovskaia AM, Goldstein LB, Bullman SH, Khan W, El-Masry EM, Abou-Donia MB. Neurological deficits induced by malathion, DEET, and permethrin, alone or in combination in adult rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2004; 67:331-356. [PMID: 14713564 DOI: 10.1080/15287390490273569] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Malathion (O,O-dimethyl-S-[1,2-carbethoxyethyl]phosphorodithionate), DEET (N,N-diethyl-m-toluamide), and permethrin [(+/-)-cis/trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxylic acid (3-phenoxyphenyl) methyl ester] are commonly used pesticides. To determine the effects of the dermal application of these chemicals, alone or in combination, the sensorimotor behavior, central cholinergic system, and histopathological alterations were studied in adult male Sprague-Dawley rats following a daily dermal dose of 44.4 mg/kg malathion, 40 mg/kg DEET, and 0.13 mg/kg permethrin, alone and in combination for 30 d. Neurobehavioral evaluations of sensorimotor functions included beam-walking score, beam walk time, inclined plane, and grip response assessments. Twenty-four hours after the last treatment with each chemical alone or in combination all behavioral measures were impaired. The combination of DEET and permethrin, malathion and permethrin, or the three chemicals together resulted in greater impairments in inclined performance than permethrin alone. Only animals treated with a combination of DEET and malathion or with DEET and permethrin exhibited significant increases in plasma butyrlcholinesterase (BChE) activity. Treatment with DEET or permethrin alone, malathion and permethrin, or DEET and permethrin produced significant increases in cortical acetylcholinesterase (AChE) activity. Combinations of malathion and permethrin or of DEET and permethrin produced significant decreases in midbrain AChE activity. Animals treated with DEET alone exhibited a significant increase in cortical m2 muscarinic ACh receptor binding. Quantification of neuron density in the dentate gyrus, CA1 and CA3 subfields of the hippocampus, midbrain, brainstem, and cerebellum revealed significant reductions in the density of surviving neurons with various treatments. These results suggest that exposure to real-life doses of malathion, DEET, and permethrin, alone or in combination, produce no overt signs of neurotoxicity but induce significant neurobehavioral deficits and neuronal degeneration in brain.
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Affiliation(s)
- Ali Abdel-Rahman
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Nagata K, Huang CS, Song JH, Narahashi T. Direct actions of anticholinesterases on the neuronal nicotinic acetylcholine receptor channels. Brain Res 1997; 769:211-8. [PMID: 9374188 DOI: 10.1016/s0006-8993(97)00707-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Recent studies have suggested that anticholinesterases including organophosphates and carbamates act directly on the nicotinic acetylcholine receptor (AChR) channel. We performed whole-cell and single-channel patch-clamp experiments to elucidate the mechanism of action of anticholinesterases on the nicotinic AChR in rat clonal phaeochromocytoma (PC12) cells. Neostigmine and carbaryl showed a biphasic effect; enhancement and suppression of carbachol-induced whole-cell currents. The currents induced by 100 microM carbachol was enhanced by the first co-application with 10 or 100 microM neostigmine, and the current was eventually suppressed below the control level during repeated co-applications. The decay phase of current was accelerated by neostigmine. Carbaryl at 0.1 microM greatly potentiated the carbachol-induced current, and at higher concentrations (0.3-3 microM), current was suppressed. In single-channel experiments, these compounds increased the short closures or gaps during channel opening without changing the single-channel conductance. Mean open time and burst duration were decreased in the presence of neostigmine and carbaryl. These results indicate that neostigmine and carbaryl directly block the nicotinic AChR channel.
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Affiliation(s)
- K Nagata
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, IL 60611, USA
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Nostrandt AC, Padilla S, Moser VC. The relationship of oral chlorpyrifos effects on behavior, cholinesterase inhibition, and muscarinic receptor density in rat. Pharmacol Biochem Behav 1997; 58:15-23. [PMID: 9264064 DOI: 10.1016/s0091-3057(96)00458-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Behavioral changes and tissue cholinesterase (ChE) inhibition were examined in animals treated with the commonly used insecticide chlorpyrifos. Adult male rats were dosed by gavage with 0, 10, 30, 60, or 100 mg/kg chlorpyrifos. Rats (n = 20/dose group) were evaluated using a functional observational battery (FOB) and an automated measure of motor activity. All rats were tested the day before dosing and at 3.5 h (the time of peak effect) after dosing; half of these (n = 10/dose) were sacrificed immediately after testing for tissue collection. The remaining rats were tested again at 24 h, followed by sacrifice. The following tissues were collected from each animal: half brain, individual brain areas from the other half of the brain (frontal cortex, hippocampus, striatum, hypothalamus, cerebellum, pons/medulla), retina, liver, heart, diaphragm, quadriceps femoris muscle, and blood (separated into whole blood, plasma, and erythrocytes). ChE activity was measured in all tissues, and muscarinic receptor density was assessed as quinuclidinyl benzilate (QNB) binding in all brain regions, heart, and retina. The lowest dose produced no behavioral effects but did produce significant ChE inhibition in most tissues at 3.5 h. Higher doses produced more ChE inhibition and cholinergic signs of toxicity. Partial recovery from behavioral effects was evident at 24 h, with little or no corresponding recovery of ChE activity. Apparent downregulation of muscarinic receptor density was noted only in striatum and pons/medulla of rats treated with the highest dose of chlorpyrifos. Correlations for behavioral and biochemical effects were generally poor because: a) the low-dose effects on ChE inhibition were not reflected in behavioral signs, and b) behavioral signs showed recovery at 24 h, whereas ChE activity did not. Examination of data for individual rats indicated that > 60% of brain ChE inhibition was reached before neurobehavioral effects were evident.
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Affiliation(s)
- A C Nostrandt
- Curriculum in Toxicology, University of North Carolina, Chapel Hill 27599, USA
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Abstract
Assessing the neurotoxic potential of organophosphate and carbamate pesticides should be greatly facilitated by the knowledge that the mechanism of action of these insecticides is presumed to be the inhibition of cholinesterase, the enzyme which controls the levels of neurotransmitter, acetycholine. Although the inhibition of cholinesterase activity is the recognized mechanism of action, many questions remain regarding the use of cholinesterase inhibition data as a critical effect for establishing risk of cholinesterase-inhibiting pesticides. Specifically, questions have arisen regarding whether blood cholinesterase inhibition correlates with inhibition in target tissues (e.g. brain or muscle) and whether cholinesterase inhibition in any tissue correlates with the adverse clinical and behavioral effects produced by exposure to cholinesterase-inhibiting pesticides. Studies in our laboratory indicate that blood cholinesterase inhibition in both acute and subchronic dosing regimens correlates with inhibition in other tissues, if measurements are taken at the appropriate times. Moreover, there is evidence in the literature and from our laboratory that cholinesterase inhibition correlates with the emergence and severity of clinical signs of poisoning by cholinesterase-inhibiting pesticides.
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Affiliation(s)
- S Padilla
- Neurotoxicology Division (MD-74B), US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Padilla S, Moser VC, Pope CN, Brimijoin WS. Paraoxon toxicity is not potentiated by prior reduction in blood acetylcholinesterase. Toxicol Appl Pharmacol 1992; 117:110-5. [PMID: 1440604 DOI: 10.1016/0041-008x(92)90224-g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The role of blood acetylcholinesterase in moderating the effects of organophosphate challenge in rats was tested. Adult male rats (n = 42) were injected (iv) either with monoclonal antibodies (MAb) to rat acetylcholinesterase (EC 3.1.1.7; AChE) or normal mouse IgG (controls). Two days later, the rats were injected (sc) with either a mild (0.17 mg/kg) or moderate dosage (0.34 mg/kg) of paraoxon or with vehicle. Neurological integrity was assessed by a functional observational battery followed by motor activity, 3 to 4 hr after dosing. Blood, brain, and diaphragm tissues were then collected for determination of AChE activity. MAb treatment reduced whole blood and plasma AChE activity by 32 and 90%, respectively, but did not affect neurobehavioral parameters or the AChE activity of brain or diaphragm. The paraoxon challenge produced dose-related neurobehavioral changes and inhibition of brain and diaphragm AChE activity to the same extent in IgG- and MAb-treated rats. Thus, significant loss in blood AChE alone produced no detectable neurobehavioral deficits and did not alter the subsequent responses to paraoxon challenge.
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Affiliation(s)
- S Padilla
- Neurotoxicology Division (MD-74B), U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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Lynch MR, Rice MA, Robinson SE. Dissociation of locomotor depression and ChE activity after DFP, soman and sarin. Pharmacol Biochem Behav 1986; 24:941-7. [PMID: 3714785 DOI: 10.1016/0091-3057(86)90440-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effect of direct intrastriatal injection of three organophosphate cholinesterase inhibitors, DFP (diisopropylphosphorofluoridate), soman (pinacolyl methylphosphonofluoridate) and sarin (isopropyl methylphosphonofluoridate) has been studied on locomotor activity in the rat. The degree of ChE inhibition has been monitored in the striatum, as well as in surrounding brain areas and blood, in order to verify the selectivity of the treatment and rule out effects attributable to actions in these areas and/or the periphery. It has been determined that while enzyme activity is inhibited in the striatum by all three compounds, only DFP significantly reduces locomotor activity at doses that produce no other observable behavioral deficits, or significant leakage into the periphery. Behavioral recovery occurs before enzyme activity returns to control levels. Possible contributions of DFP's action on other neurotransmitters and on ChE in other brain areas to the inhibition of locomotor activity are discussed.
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Hussein MF, Ahmed NA, Rawi SM. The alterations of rat brain GABA and glutamine induced by the organophosphorus compound cyolane. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1986; 84:165-70. [PMID: 2873949 DOI: 10.1016/0742-8413(86)90184-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Levels of the amino acids GABA and glutamine were determined in the whole brain of the white albino rat Rattus norvegicus after daily injection of 1/2, 1/4, 1/8, 1/16, 1/32 and 1/100 LD50 of cyolane. With 1/2 LD50 an increase in the level of both GABA and glutamine in the brain was recorded. Dose levels of 1/4 and 1/8 LD50 caused an increase in the level of GABA and a decrease in glutamine concentration followed by an increase from the 7th and 11th days for 1/4 and 1/8 LD50, respectively. The induced increase in GABA level started from the 2nd week for 1/16 and 1/32 LD50 and from the 3rd week for 1/100 LD50. Dose levels of 1/16, 1/32 and 1/100 LD50 caused a fluctuating increase in glutamine concentration starting from the 2nd, 3rd and 6th weeks, respectively, which was followed by a fluctuating decrease at the 9th week for 1/32 and 1/100 LD50. These findings support previous findings that the enhanced transformation of glutamic acid to GABA and glutamine is a result of a disturbance in the metabolism of the glutamic acid-GABA and the glutamic acid-glutamine systems in the rat brain.
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Kenley RA, Howd RA, Uyeno ET. Effects of PAM, proPAM, and DFP on behavior, thermoregulation, and brain AChE in rats. Pharmacol Biochem Behav 1982; 17:1001-8. [PMID: 7178195 DOI: 10.1016/0091-3057(82)90485-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The effects of pyridine-2 aldoxime methyl iodide (PAM), N-methyl-1,6-dihydro-pyridine-2-carbaldoxime hydrochloride (proPAM), and diisopropyl phosphorofluoridate (DFP) on performance of a conditioned avoidance response (CAR), body temperature, and in vivo acetylcholinesterase (AChE) activity in five brain regions in the rat were examined. Sublethal doses of DFP (1.5 to 2.5 mg/kg, IP) markedly degraded CAR performance. This effect was antagonized by 5 mg/kg, subcutaneously injected (SC) atropine. A 50 mg/kg, SC dose of PAM had no effect on the CAR, but an equal dose of proPAM caused a transient deterioration of performance. Given 10 min or 2 hr after DFP, 50 mg/kg proPAM initially exacerbated the behaviorally toxic effects of DFP. Neither PAM nor proPAM antagonized DFP-induced hypothermia. PAM did not reactivate DFP-inhibited brain AChE, and proPAM reactivated it by only 6 to 12% of control activity.
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Crowder LA, Lanzaro GC, Whitson RS. Behavioral effects of methyl parathion and toxaphene exposure in rats. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 1980; 15:365-378. [PMID: 7400539 DOI: 10.1080/03601238009372189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The behavior of rats exposed peri- and postnatally to methyl parathion (MP) and toxaphene (T) was examined with a variety of maturational and learning tests. Females received daily oral doses of 1.0 mg/kg MP or 1.0 mg/kg MP + 2.0 mg/kg T between Days 7-15 of pregnancy. With T alone, rats of the postnatal group were dosed daily with 6 mg/kg for 21 days, while in the perinatal study females received 6 mg/kg daily from Day 7 of pregnancy until parturition. Rat pups exposed to sublethal doses of MP and T in combination or alone demonstrated few significant changes in learning ability as measured by a simple two-choice maze, motor skills, or behavior.
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Kurtz PJ, Weeks MH. Effects of single and repeated exposures to abate on rat behavior and cholinesterase activity. Toxicology 1979. [DOI: 10.1016/s0300-483x(79)80008-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bracy OL, Doyle RS, Kennedy M, McNally SM, Weed JD, Thorne BM. Effects of methomyl and ethanol on behavior in the Sprague-Dawley rat. Pharmacol Biochem Behav 1979; 10:21-5. [PMID: 571608 DOI: 10.1016/0091-3057(79)90163-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Emotional behavior and activity levels were studied following administration of ethanol and/or a carbamate pesticide, methomyl, to rats via a ground chow diet. Acetylcholinesterase levels were lowered following the experimental diets. The group having the greatest reduction in AChE, the methomyl group, showed less evidence for habituation in an open-field test. No differences relative to control subjects were noted on handling and muricide tests.
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Kurtz PJ. Dissociated behavioral and cholinesterase decrements following malathion exposure. Toxicol Appl Pharmacol 1977; 42:589-94. [PMID: 601800 DOI: 10.1016/s0041-008x(77)80044-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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