New horizons: future directions in neurotoxicology.

Neurotoxicology is a relatively young discipline that has undergone significant growth during the last 25 years. During the late 1970s and 1980s, numerous national and international conferences and meetings were devoted to the topic of neurotoxicology, the formation of societies or specialty sections related to neurotoxicology, and the establishment of two independent peer-reviewed journals devoted to neurotoxicology. This decade was also associated with a rapid increase in our knowledge of chemical effects on the structure and function of the nervous system. During the 1990s, regulatory agencies such as the U.S. Environmental Protection Agency accepted neurotoxicology as a crucial end point and neurotoxicity testing and risk assessment guidelines were published. Neurotoxicology has also been accepted at the international level as evidenced by environmental criteria documents published by the International Programme on Chemical Safety and testing guidelines by the Organization of Economic Cooperation and Development. In recent years, there has been increased concern that the etiology of some neurodegenerative diseases may be associated with exposure to neurotoxic agents and that subpopulations of humans such as children and the elderly may be differentially sensitive to neurotoxic exposure. In the future, mechanistic information derived from basic research will be used in the identification and characterization of chemicals with neurotoxic potential.