ABSTRACT
INTRODUCTION Advances in molecular biology in the last two decades have produced a powerful set of tools for the analysis of structure, function, and internal dynamics of eukaryotic cells, both in vitro and in vivo. The ability to clone genes, measure their expression, and to assess their function by modulating the expression of the native gene or their mutant versions introduced into cells, are the central driving forces for this technological revolution. The confl uence of these molecular techniques with the similar developments in cell biology, allowing the isolation and cultivation of cells in vitro in primary cultures, has greatly impacted our understanding of biology of differentiated cells from various mammalian organs including the brain. Despite the contributions of these complementary approaches to the study of basic cell biology and their successful applications to drug discovery, their use to address the questions of toxicology lags behind. A recent report released by the National Research Council of the National Academy of Sciences (U.S.A.) titled “Toxicity Testing in the 21st Century: A Vision and a Strategy” (1) , places great emphasis on the use of in vitro assays, preferably using human cells in culture, in its vision of the future of toxicity testing as an alternative to the time-and resource-intensive methodologies currently used. This chapter highlights advances in molecular tools in the context of basic biology of neuronal cells, discusses their extant applications to neurotoxicology, and addresses their future applicability. While the application of the molecular tools in vitro forms the focus of this review, it should be recognized these same tools have been vital to studies at the whole organism level, notably through the creation of transgenic and knockout animal models ( 2-4 ), which will be discussed only as is relevant to the in vitro approaches or applications. Further, advances in recombinant DNA-based expression of proteins in heterologous organisms such as Escherichia coli and yeast have resulted in their use as antigens for the production of monoclonal antibodies highly specifi c to these proteins; these have been vital tools for immunohistochemical studies of cells in vitro as well as in vivo. However, this has been a well-established technology for well over a decade and will not be discussed in this review.
