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The structural and functional characterization at the cDNA and protein structure level of an L-glutamate/L-aspartate transporter (GLAST) from rat brain was reported. L-glutamate and L-aspartate transport systems are important in the termination of neurotransmitter signals at the excitatory synapses. GLAST was shown to be a sodium ion-dependent transporter with exclusive mRNA expression in the Purkinje cell layer of the cerebellum. It was suggested that GLAST could have a role in the regulation of neurotransmitter levels in the central nervous system.

Once again, genomics is about to change drug development. Following its major impact on target discovery and assay development, which increased the number of compounds at early stages of the process, genomics is now zeroing in on the prediction of potential toxicological problems of compounds. Toxicogenomics is the analysis of toxicological processes at the transcriptome level of a target organ or cell. By simultaneously monitoring the effect of a compound on the transcription levels of hundreds to thousands of genes, toxicogenomics can provide an enormous amount of data. This data bears information on the way in which compounds act at the molecular level, reaching far beyond the mere conclusion of whether or not a particular toxicological outcome is elicited. By compiling transcription profiles for well-known toxicants, we are beginning to learn how to analyze this novel type of data in the context of mechanistic and predictive toxicology.