1
|
Bellum S, Thuett KA, Grajeda R, Abbott LC. Coordination Deficits Induced in Young Adult Mice Treated with Methylmercury. Int J Toxicol 2016; 26:115-21. [PMID: 17454251 DOI: 10.1080/10915810701225190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Male and female C57BL/6J mice starting at postnatal (P) day 34 were exposed orally to five divided doses totaling 1.0 or 5.0 mg/kg of methylmercury (MeHg; given as methylmercuric chloride) or sterile deionized water in moistened rodent chow. After a 5-day waiting period, control and MeHg-treated mice were subjected to a standard battery of behavior tests for balance and motor coordination. Latency to falling on the accelerating rota-rod was significantly decreased in 5.0 mg/kg MeHg-exposed mice when compared to control mice. In the open field, horizontal exploration with respect to total distance traveled during the first 5 min on the first test day was significantly reduced in 1.0 mg/kg MeHg-exposed mice when compared to control mice. Rearing activity was not affected by MeHg treatment. In the footprint analysis, angle of foot placement measured in 1.0 mg/kg MeHg-treated mice was significantly greater compared to control mice. Base stance and stride length were unaffected by MeHg treatment. On the vertical pole test, 10 mice from each treatment group fell off the pole during the time the pole was shifted from a horizontal position to a vertical position, whereas none of the control mice fell. These results indicate that short-term, low to moderate doses of MeHg in young adult mice can be detrimental to motor coordination and balance.
Collapse
Affiliation(s)
- Sairam Bellum
- Safety Assessment, Merck Research Laboratories, West Point, Pennsylvania, USA
| | | | | | | |
Collapse
|
2
|
Bellum S, Thuett KA, Bawa B, Abbott LC. The effect of methylmercury exposure on behavior and cerebellar granule cell physiology in aged mice. J Appl Toxicol 2012; 33:959-69. [DOI: 10.1002/jat.2786] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 04/26/2012] [Accepted: 04/27/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Sairam Bellum
- Safety Assessment, Merck Research Laboratories; West Point; PA; 19486; USA
| | - Kerry A. Thuett
- ChemRisk; 101 2nd Street, Suite 700; San Francisco; CA; 94105; USA
| | - Bhupinder Bawa
- Department of Diagnostic Medicine/Pathology; Kansas State University, College of Veterinary Medicine; 101 Trotter Hall; Manhattan; KS; 66506-5601; USA
| | - Louise C. Abbott
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, 4458 TAMU; Texas A&M University; College Station; TX; 77843-4458; USA
| |
Collapse
|
3
|
Komulainen H, Tuomisto J. Interference of Methyl Mercury with Monoamine Uptake and Release in Rat Brain Synaptosomes. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1600-0773.1981.tb01611.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
4
|
Shigematsu J, Yasuda T, Goto Y, Tanaka K, Tobimatsu S. Chronic effects of methylmercury on the cerebral function in rats. J Neurol Sci 2000; 182:69-75. [PMID: 11102642 DOI: 10.1016/s0022-510x(00)00454-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We studied the effects of the long-term and small-dose administration of methylmercury chloride (MMC) on the cerebral function in rats. MMC, at a dose of 0.7 mg/kg/day, was subcutaneously injected for 85 consecutive days in nine adult male Sprague-Dawley rats. They were then sacrificed on the final day of exposure (MMC group) after both completing observations on behavioral changes and also determining the local cerebral glucose utilization (LCGU) as an indicator of the cerebral neuronal activities. Histological examinations of the brain and the sciatic nerve were also performed. In addition, seven rats who received physiological saline also served as a control. LCGU significantly decreased in the visual cortex, lateral geniculate nucleus and medial geniculate nucleus without any accompanying histological alterations. Severe axonal degeneration of the sciatic nerve was also observed, which corresponded to the previously described crossed leg phenomenon. The present results suggest that the damage to the peripheral nerve was much more severe than that to the brain, which caused behavioral changes. Although no cerebral morphological changes were observed, brain dysfunction showed a selective involvement of the visual and auditory systems. This finding suggests that LCGU is a sensitive method for detecting the subclinical cerebral dysfunction caused by long-term and small-dose MMC intoxication in the rat brain.
Collapse
Affiliation(s)
- J Shigematsu
- Department of Clinical Neurophysiology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, 812-8582, Fukuoka, Japan.
| | | | | | | | | |
Collapse
|
5
|
Shigematsu J, Yasuda T, Goto Y, Tanaka K, Tobimatsu S, Kato M. Recovery of brain dysfunction after methylmercury exposure in rats. J Neurol Sci 2000; 182:61-8. [PMID: 11102641 DOI: 10.1016/s0022-510x(00)00450-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We studied the time course of central nervous system (CNS) involvement after the termination of methylmercury exposure to rats, in order to investigate whether or not the involvement still progresses even after the termination of exposure. Methylmercury chloride (MMC), at a dose of 2 mg/kg/day, was subcutaneously injected for 25 consecutive days in 12 adult male Sprague-Dawley rats. Six of them were sacrificed on the final day of exposure (group A) after completing the observations of behavioral changes and determining the local cerebral glucose utilization (LCGU) as an indicator of cerebral neuronal activities. Histological examinations of the brain and the sciatic nerve were done. The other six rats were further followed up for 90 days after the termination of exposure (group B). In addition, six rats that received physiological saline served as a control. Group A showed a significant reduction of LCGU without any accompanying cerebral histological alterations and a moderate loss of myelinated fibers in the sciatic nerve. Group B showed normal LCGU rates while severe axonal degeneration of the sciatic nerve was found on the final day of the 90-day follow-up period. The present results demonstrate that a transient involvement of the CNS can occur after MMC exposure. In addition, a complete recovery may occur when the process is mild enough not to cause histological alterations. In contrast, the involvement of the peripheral nerve is much more severe than that of the CNS and it was observed to progress even after the cessation of MMC exposure. Therefore, it seems unlikely, at least in rats, that a steadily progressive course occurs in the CNS but not in the peripheral nerves over a long period of time after MMC exposure.
Collapse
Affiliation(s)
- J Shigematsu
- Department of Clinical Neurophysiology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, 812-8582, Fukuoka, Japan.
| | | | | | | | | | | |
Collapse
|
6
|
Kung MP, Kostyniak P, Olson J, Malone M, Roth JA. Studies of the in vitro effect of methylmercury chloride on rat brain neurotransmitter enzymes. J Appl Toxicol 1987; 7:119-21. [PMID: 2887607 DOI: 10.1002/jat.2550070208] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The in vitro effect of methylmercury (MM) on the enzymatic activities of brain cell specific marker enzymes, choline acetyltransferase (CAT), glutamic acid decarboxylase (GAD), 2',3'-cyclic nucleotide phosphohydrolase (CNP), glutamine synthetase (GS) and enolase was examined. The results demonstrate that at 100 microM MM, GS activity was not affected whereas a small decrease in the activity of both GAD (20%) and enolase (10%) was observed. CNP and CAT activity appeared to be more sensitive toward MM with 100 microM MM producing inhibition of 50% and 30%, respectively. The addition of sulfhydryl protecting reagents such as DTT or sodium thioglycolate can restore the enzyme activities to normal control levels despite prior exposure of the enzymes to MM.
Collapse
|
7
|
Aschner M. Effects of systemic methyl mercury-adulterated water consumption on fast axonal transport in the rat visual system. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1986; 59:349-55. [PMID: 2433893 DOI: 10.1111/j.1600-0773.1986.tb00183.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The present study was designed in an effort to determine whether changes in fast axonal transport in the mature rat visual system can be directly correlated with the onset of neurological dysfunction. Methyl mercury was administered in the drinking water at a concentration of 54 micrograms Hg/ml. Fast axonal transport of proteins in the optic nerve and tract was quantified by scintillation spectrometry of protein-bound radioactivity along the visual pathway after an intraocular injection of 3H-proline. At 8 hours after injection the labeled protein had reached the lateral geniculate body both in controls and treated animals. However, two-way analysis of variance revealed a significant decrease in the volume of transported protein-bound radioactivity along the visual pathway. Thus, while the rate of fast axonal transport does not seem to be correlated with the onset of motor dysfunction, the onset of neurological symptoms may be associated with abnormal transport capacity. Treatment lowered body weight to the same extent in males and females. Hind limb cross-over occurred after 25.6 +/- 0.8 days and was followed quickly by hind limb paralysis (32 +/- 0.6 days). The cerebellum revealed pyknotic nuclei throughout the internal granular layer. Purkinje cells appeared normal. No pathological changes were noted in the kidneys.
Collapse
|
8
|
Aschner M, Rodier PM, Finkelstein JN. Reduction of axonal transport in the rat optic system after direct application of methylmercury. Brain Res 1986; 381:244-50. [PMID: 2428435 DOI: 10.1016/0006-8993(86)90073-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fast axonal transport of proteins in the optic nerve and tract was quantified by scintillation counts of protein-bound radioactivity along the visual pathway after an intraocular injection of [3H]proline. In control rats the label traveled at a rate of about 60 mm/day, reaching the optic chiasm at 4 h and the lateral geniculate body at 8 h postinjection. When methylmercury was injected simultaneously with [3H]proline, the label traveled at a rate of about 30 mm/day. At 8 h postinjection, the labeled protein had reached the optic chiasm, but the more distal pathway was unlabeled. The same pattern was observed histologically by emulsion autoradiography of the pathway. Some label was detected in the lateral geniculate of methylmercury-treated animals at 8 h, but this may have resulted from local incorporation, as judged by a similar level of labeling in the contralateral visual pathway. Alternatively, it may be the case that a small fraction of the axons in the treated pathway continued to transport proteins in a normal fashion. The very heavy label observed throughout the pathway in controls was present only in the proximal half of the pathway in methylmercury-treated rats. Methylmercury significantly reduced incorporation of [3H]proline in the rat retina, but this reduction was not as great as the effect in the optic nerve. In contrast, cycloheximide, a potent protein synthesis inhibitor, reduced labeled protein in the optic nerve only to the same extent as it reduced incorporation. These results suggest that methylmercury's effect on transport is not dependent solely on its effects on protein synthesis, but represents a separate mechanism of neurotoxicity.
Collapse
|
9
|
Aschner M. Changes in axonally transported proteins in the rat visual system following systemic methyl mercury exposure. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1986; 59:151-7. [PMID: 2430425 DOI: 10.1111/j.1600-0773.1986.tb00147.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In an effort to understand the effect of methylmercury on protein synthesis and axonal transport, we have analysed the composition and rate of axonally transported proteins in the retinal ganglion cells of the mature rat. By means of scintillation spectrometry and autoradiography, it was established that systemic exposure to 4 mg Hg/kg/day for four to six days, or twelve days, resulted in an increased rate and volume of transported protein-bound radioactivity in the visual system of the mature rat. In an effort to characterize these changes, the composition of transported polypeptides was analysed by means of SDS polyacrylamide gel electrophoresis. Selective changes in the composition of transported polypeptides were evident. These changes of a small subset of proteins known as GAPs (growth-associated proteins) are consistent with the suggestion that they may have been involved in growth-specific functions during the early stages of methyl mercury exposure. We concluded that, during this period, retinal ganglion cells may express growth-related genes and engage in regenerative processes.
Collapse
|
10
|
Eldefrawi AT, Mansour NA, Eldefrawi ME. Insecticides affecting acetylcholine receptor interactions. Pharmacol Ther 1982; 16:45-65. [PMID: 6752971 DOI: 10.1016/0163-7258(82)90031-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
11
|
Hershberger MV, Maki AH. Heavy-atom effects associated with methylmercury(II) binding to rabbit glyceraldehyde-3-phosphate dehydrogenase. Biopolymers 1980; 19:1329-44. [PMID: 7397316 DOI: 10.1002/bip.1980.360190709] [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: 01/25/2023]
|
12
|
Hershberger MV, Maki AH. Triplet state properties of the methylmercury(II)-tyrosine complex. J Inorg Biochem 1980. [DOI: 10.1016/s0162-0134(00)80076-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
13
|
Zimmer L, Carter DE. Effects of complexing treatment administered with the onset of methyl mercury neurotoxic signs. Toxicol Appl Pharmacol 1979; 51:29-38. [PMID: 524372 DOI: 10.1016/0041-008x(79)90005-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
14
|
von Burg R, Lijoi A, Smith C. Oxygen consumption of rat tissue slices exposed to methylmercury in vitro. Neurosci Lett 1979; 14:309-14. [PMID: 530506 DOI: 10.1016/0304-3940(79)96166-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The physiological significance of damage from methylmercury exposure was assessed by comparing the oxygen consumption of rat liver, kidney and brain tissue slices after direct exposure to methylmercury chloride. Standard Warburg respirometers were used. Methylmercury chloride was added during the preparation of the experimental flasks and the tissues were preincubated for up to one hour. Oxygen consumption was accelerated by tipping sodium succinate into the main chamber from the sidearm. During the ensuing 3 h of observation, oxygen was consumed at a uniform rate and all the organ slices were equally inhibited at the respective concentrations of methyl-mercury tested. Brain slices without excess succinate were slightly more sensitive to the presence of methylmercury, but this difference was significant only at 2 . 10(-4) M methylmercury. The results suggest (a) that all three organs are about equally sensitive to direct toxic insult by methylmercury under standardized conditions, (b) that any difference observed is due to metabolic reserve capacity and (c) that organ damage induced by methylmercury cannot be attributed to a direct interference with the glycolytic machinery of the cells since organ tissue levels at the point of intoxication are considerably lower.
Collapse
|
15
|
Morganti JB, Lown BA, Stineman CH, Massaro EJ. Cerium tissue/organ distribution and alterations in open field and exploratory behavior following repeated exposure of the mouse to citrate complexed cerium. GENERAL PHARMACOLOGY 1978; 9:257-61. [PMID: 680557 DOI: 10.1016/0306-3623(78)90045-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
16
|
|
17
|
Eldefrawi ME, Mansour NA, Eldefrawi AT. Interactions of acetylcholine receptors with organic mercury compounds. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1977; 84:449-63. [PMID: 899953 DOI: 10.1007/978-1-4684-3279-4_20] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Micromolar concentrations of methylmercury and several organic mercury fungicides were found to block binding of [3H]acetylcholine (ACh) to the ACh-receptor of the electric organ of the electric ray, Torpedo ocellata. The same compounds had little or no effect on the catalytic activity of ACh-esterase of the same tissue. [14C]Methyl-mercury bound to the purified ACh-receptor with high affinity (Kd=7micrometer) and there were 6.5 +/- 0.5 binding sites for each ACh-binding site. Binding of methylmercury was highly cooperative with a Hill coefficient of 2.6. This binding was irreversible by redialysis in methylmercury - free medium, however, the bound [14C]methylmercury was easily displaced from the receptor protein with micrometer concentrations of BAL or penicillamine. Methylmercury also blocked binding of [3H] nicotine and [3H]pilocarpine to the nicotinic and muscarinic ACh-receptors of the rat brain, respectively. The data suggest that the ACh-receptor may be a target for methylmercury and other organic mercury compounds.
Collapse
|
18
|
Lown BA, Morganti JB, Stineman CH, Massaro EJ. Differential effects of acute methylmercury poisoning in the mouse arising from route of administration: LD50, tissue distribution and behavior. GENERAL PHARMACOLOGY 1977; 8:97-101. [PMID: 598681 DOI: 10.1016/0306-3623(77)90035-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
19
|
Taylor LL, DiStefano V. Effects of methylmercury on brain biogenic amines in the developing rat pup. Toxicol Appl Pharmacol 1976; 38:489-97. [PMID: 13517 DOI: 10.1016/0041-008x(76)90180-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
20
|
Morganti JB, Lown BA, Salvaterra P, Massaro EJ. Effects on open-field behavior of mice exposed to multiple doses of methyl mercury. GENERAL PHARMACOLOGY 1976; 7:41-4. [PMID: 971798 DOI: 10.1016/0306-3623(76)90030-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
21
|
Salvaterra P, Massaro EJ, Morganti JB, Lown BA. Time-dependent tissue/organ uptake and distribution of 203Hg in mice exposed to multiple sublethal doses of methyl mercury. Toxicol Appl Pharmacol 1975; 32:432-42. [PMID: 1154404 DOI: 10.1016/0041-008x(75)90233-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
22
|
Bull RJ, Lutkenhoff SD. Changes in the metabolic responses of brain tissue to stimulation, in vitro, produced by in vivo administration of methyl mercury. Neuropharmacology 1975; 14:351-9. [PMID: 239365 DOI: 10.1016/0028-3908(75)90017-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
23
|
Magnaval R, Batti R, Thiessard J. Methyl mercury effect on rat liver mitochondrial deshydrogenases. EXPERIENTIA 1975; 31:406-7. [PMID: 164366 DOI: 10.1007/bf02026343] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
24
|
Hösli E, Hösli L. The effects of methyl mercury on morphological and histochemical properties of human and rat spinal cord and cerebellum in tissue culture. EXPERIENTIA 1974; 30:1300-4. [PMID: 4435173 DOI: 10.1007/bf01945197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
25
|
|
26
|
Morganti JB, Lown BA, Stineman C, Massaro EJ. Effects of food deprivation on open-field behavior of mice exposed to methyl mercury. Psychol Rep 1974; 35:901-2. [PMID: 4438538 DOI: 10.2466/pr0.1974.35.2.901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The joint effects of methyl mercury and food deprivation on activity of 40 mice in an open field were examined. Analysis gave a significant main effect for mercury but not deprivation, and a significant interaction between mercury and deprivation. Simple tests indicated that food deprivation enhanced the depression of activity associated with exposure to mercury.
Collapse
|