Central nervous system manganese

Metabolic Functions. Manganese is essential for normal body stmcture, reproduction, normal functioning of the central nervous system, and activation of numerous enzymes (126). Synthesis of the mucopolysaccharide chondroitin sulfate involves a series of reactions where manganese is required in at least five steps (127). These reactions are responsible for formation of polysaccharides and linkage between the polysaccharide and proteins that form... 

The uptake of manganese by plants and its transport within plants has been reviewed. " Reviews describing Mn speciation in the blood and the transport kinetics of Mn into the central nervous system of mammals have appeared. Manganese has a unique capacity to be taken up via the olfactory pathways and pass trans-neuronally to other parts of the brain. ... 

Toxicology. The major concern of humans exposed to manganese is its effects on the central nervous system after chronic exposure. 

Toxicology. Manganese tetroxide affects the central nervous system, and toxicity occurs mostly in chronic form (manganism). 

Toxicology. 2-Methylcyclopentadienyl manganese tricarbonyl (MMT) causes central nervous system effects and liver, kidney, and pulmonary damage in animals. 

Although trace amounts of manganese are essential for animals, in large quantities the metal can cause acute and chronic poisoning. Chronic inhalation of metal dust or fumes can cause manganism, a nonfatal disease affecting the central nervous system. The symptoms are mental disorder and disturbance in speech. 

Solvents, such as chlorinated hydrocarbons, toluene, benzene, and xylene, can cause a feeling of euphoria, but they can be deadly toxins. Small, daily doses may cause dizziness, mental confusion, and fatigue high doses will cause permanent damage to the central nervous system. Lead, mercury, and manganese ion poisoning will alter and destroy central and peripheral nerve function and cause personality changes. 

M. Aschner, K. E. Vrana, W. Zheng, Manganese uptake and distribution in the central nervous system (CNS), Neurotoxicology, 20 (1999), 173-180. 

R. T. Ingersoll, E. B. Montgomery, H. V. Aposhian, Central nervous system toxicity of manganese. II. Cocaine or reserpine inhibit manganese concentration in the rat brain. 

Manganese toxicity is also known to represent a serious health hazard to humans, with toxic intakes of the element (either through the air or diet) resulting in severe pathologies, particularly of the central nervous system (15-19). The first observation of Mn toxicity in humans was made by Couper in 1837 (15) (Table II), who reported a paralytic disease in workers of a pyrolusite (Mn dioxide) mill. 

Exposure to neurotoxicants or neurotoxic chemical substances causes severe adverse health effects to the nervous system, which is very sensitive to organometallic compounds and sulfide compounds. These compounds disrupt the normal functioning of the central nervous system, peripheral nerves or sensory organs, and the conduction of nerve impulses. Thus, chemical substances are considered neurotoxicants when they induce a consistent pattern of neural dysfunction. The chemical substances include but are not limited to carbon disulfide, manganese, methyl mercury, organic phosphorous insecticides, tetraethyl lead, thallium, and trialkyl tin compounds. 

Brain extracellular concentrations of amino acids and divalent metals (e.g., manganese) are primarily regulated by astrocytes. Adequate glutamate homeostasis is essential for the normal functioning of the central nervous system (CNS), for example, glutamate is important for nitrogen metabolism and, along with aspartate, is the primary mediator of the excitatory... 

Elder A, Gelein R, Silva V, et al. Translocation of inhaled ultrafine manganese oxide particles to central nervous system. Environ Health Perspect 2006 114(8) 1172—8. 

Roels H, Lauwerys R, Buchet J-P, et al Epidemiological survey among workers exposed to manganese effects on lung, central nervous system, and some biological indices. Am J Ind Med 11 307-327,1987... 

A number of studies have been conducted that investigated various facets of the distribution of inorganic manganese in animal models. The studies utilized a number of routes of administration, and the results suggested that route may play an important role in distribution. In an intraperitoneal study performed in monkeys, manganese was reported in all tissues studied. The highest levels were found in the pancreas, liver, and kidney, and the lowest levels were found in the blood levels in the central nervous system were... 

The central nervous system is the primary target of manganese toxicity. Although it is known that manganese is a cellular toxicant that can impair transport systems, enzyme activities, and receptor functions, the principal manner in which manganese neurotoxicity occurs has not been clearly established (Aschner and Aschner 1991). 

Measurement of altered levels of dopamine and other neurotransmitters in the basal ganglia has proven to be a useful means of evaluating central nervous system effects in animals (e.g., Bonilla and Prasad 1984 Eriksson et al. 1987a, 1987b), and these changes are often observed before any behavioral or motor effects are apparent (Bird et al. 1984). No noninvasive methods are currently available to determine whether there are decreased dopamine levels in the brain of exposed humans, but decreased urinary excretion of dopamine and its metabolites has been noted in groups of manganese-exposed workers (Bernheimer et al. 1973 ... 

Siqueira and Moraes 1989). However, the relationship between manganese effects on peripheral versus central dopamine levels has not been clearly defined, and given the lack of change in dopamine content in substantia nigra of humans exposed to manganese, the relevance of the animal studies to central nervous system disorder is questionable. 

Tjalve H, Henriksson J, Tallkvist J, et al. 1996. Uptake of manganese and cadmium from the nasal mucosa into the central nervous system via olfactory pathways in rats. Pharmacol Toxicol 79 347-356. 

Weiner WJ, Nausieda PA, Klawans HE. 1977. Effect of chlorpromazine on central nervous system concentrations of manganese, iron, and copper. Life Sci 20 1181-1186. 

Mn(II) is taken up into bacteria by a multitude of different uptake systems. Toxicity of Mn(II) to bacteria is generally low compared to other transition metals (Nies 1999). Manganese is toxic to plants and the central nervous system of mammals (Fageria et al. 2002, Ingersoll et al. 1995). It may be detoxified in plants by sequestration to silicon (Iwasaki et al. 2002, Rogalla and Romheld 2002), while efHux-mediated manganese resistance in bacteria has not been described. It may, however, be used as an electron acceptor in... 

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