Neurotoxins and degeneration in the central nervous system.

Numerous examples exist where neurotoxins have been shown to induce selective death of certain groups of nerve cells. While the peripheral nerves are particularly vulnerable, neurotoxins are also capable of generating models of the major degenerative disorders of the central nervous system: dementia of Alzheimer's type, Parkinsonism, and amyotrophic lateral sclerosis. Important organic toxins, in this context, include certain pyridines, amines, aminoacids, nitriles, hexacarbons, and sulphides. Inorganic toxins include free radicals and certain metals. Toxins may also be classified according to their origin--exogenous or endogenous. This review will not consider neurological damage that can result from exposure to alcohol, or neurological adverse reactions to medications.