Organic solvents nervous system

AH volatile organic solvents are toxic to some degree. Excessive vapor inhalation of the volatile chloriaated solveats, and the central nervous system depression that results, is the greatest hazard for iadustrial use of these solvents. Proper protective equipment and operating procedures permit safe use of solvents such as methylene chloride, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene ia both cold and hot metal-cleaning operations. The toxicity of a solvent cannot be predicted from its chlorine content or chemical stmcture. For example, 1,1,1-trichloroethane is one of the least toxic metal-cleaning solvents and has a recommended threshold limit value (TLV) of 350 ppm. However, the 1,1,2-trichloroethane isomer is one of the more toxic chloriaated hydrocarboas, with a TLV of only 10 ppm. 

Grasso P. 1988. Neurotoxic and neurobehavioral effects of organic solvents on the nervous system. Occupational Medicine State of the Art Reviews. 3 525-539. 

Prockop L, Couri D. 1977. Nervous system damage from mixed organic solvents. In Sharp CW, ed. Review of inhalants Euphoria to dysfunction. Washington, DC U.S. Government Printing Office,... 

Note Moderately polar solvent soluble in water and most organic solvents flammable highly toxic by ingestion and inhalation absorbed through the skin may cause central nervous system depression, necrosis of the liver and kidneys incompatible with strong oxidizers. Synonyms diethylene ether, 1,4-diethylene dioxide, diethylene dioxide, dioxyethylene ether. 

Xylenes and ethylbenzene (Figure 13.7) are common gasoline constituents, industrial solvents, and reagents, so human exposure to these materials is common. The absorption (primarily through inhalation), metabolism, and effects of these solvents are generally similar to those of toluene. Effects are largely on the central nervous system. Effects of xylenes and ethylbenzene on organs other than the central nervous system appear to be limited. 

Pure hexamethyldisilazane is a colourless transparent liquid (the boiling point is 126 °C) dissolves well in inert organic solvents and is easily hydrolysed with water. It is toxic and has narcotic properties. Its vapours cause the inflammation of mucous membranes and the central nervous system they change the composition of blood. 

Organic solvents are usually classified according to their chemical composition. The aliphatic hydrocarbons, which are straight or branched chains saturated with hydrogen, act primarily as depressants to the central nervous system, but otherwise they are generally as inert biochemically as they are chemically. 

It has been suggested that the adverse effects of organic solvents on the nervous system may be, at least in part, mediated by effects on dopaminergic function (17), perhaps via active metabolites (18). The proposed metabolites are shown in Table 1. 

World Health Organization (WHO), Nordic Council of Ministers. 1985. Organic solvents and the central nervous system, EH5, 1-39. Copenhagen, Denmark World Health Organization and Nordic Council of Ministers. 

Although inhalant abuse is now recognized as a worldwide problem, organic solvents are currently the least studied drugs of abuse. For example, relatively little is known about the underlying cellular mechanisms of action through which these substances produce their effects in the central nervous system."... 

The literature on the toxicity of benzene in humans is extensive. The acute effects of benzene exposure generally differ markedly from the chronic effects. Acute exposure to high doses of benzene in air (at concentrations in excess of 3000 ppm) causes symptoms typical of organic solvent intoxication. Symptoms may progress from excitation, euphoria, headache, and vertigo, in mild cases, to central nervous system depression, confusion, seizures, coma, and death from respiratory failure in severe cases. The rate of recovery depends on the initial exposure time and concentration, but, following severe intoxication, the symptoms may persist for weeks. 

Different ion channels maintain the stability of excitable membranes that are necessary for normal functioning of the body. Saxitoxin, tetrodotoxin, and DDT all cause toxicity by blocking the sodium channel in excitable membranes. On the other hand, organic solvents cause toxicity by changing the membrane fluidity of the neurones in the central nervous system. 

Prolonged TCE exposure has been associated with impairment of peripheral nervous system function, persistent neuritis and temporary loss of tactile sense and paralysis of the fingers after direct solvent contact. Chromosomal effects have been reported in those involved in the use of TCE for degreasing and symptoms of systemic lupus erythematosis have been reported after chronic TCE exposure. In addition, organic dementia has been noted after occupational exposure to TCE and there have been some reports of an association between exposure and scleroderma, an autoimmune disease. 

Holmberg PC. 1979. Central-nervous system defects in children born to mothers exposed to organic solvents during pregnancy. Lancet 2 177-179. 

Elofsson SA, Gamberale F, Hindmarsh T, et al. Exposure to organic solvents. A cross-sectional epidemiologic investigation on occupationally exposed car and industrial spray painters with special reference to the nervous system. Scand J Work Environ Health 1980 239-73. 

The mechanism by which 1,1,1-trichloroethane and other organic solvents depress the central nervous system is poorly understood, but is thought to involve interactions of the parent compound with lipids and/or proteinaceous components of neural membranes (Evans and Balster 1991). No known methods specifically counteract the central nervous system effects of 1,1,1-trichloroethane. Because the specific cellular or biochemical nature of central nervous system depression is poorly understood, it is difficult to propose any method to interfere with this effect of 1,1,1 -trichloroethane, other than to prevent further exposure to the compound so that it can be cleared from the body. 

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