Transient expression of the glial glutamate transporters GLAST and GLT in hippocampal neurons in primary culture

The extracellular glutamate concentration is kept low by glutamate transporters in the plasma membranes. Here we have studied the expression of the glutamate transporters GLAST, GLT and EAAC during the in vitro development of embryonic hippocampal neurons grown in a defined (serum free) medium. Immunochemistry studies showed that both the GLAST and GLT proteins are expressed in a subpopulation of neurons at the early, but not at the later stages of the cultures. Glial cells expressing the GLAST and GLT proteins were found at all stages. EAAC was only detected in neurons. This is one of the first evidence of a neuronal ability to express GLAST.