PBIO SEMINAR SERIES

Neural-glial interactions in the CNS

Wednesday - January 30, 2008
07-08 SEMINAR SERIES

Craig Jahr
Senior Scientist Vollum Institute - OHSU
Speaker's website

Host: Fred Rieke

The use of glutamate as the primary excitatory neurotransmitter presents the CNS with a challenge. On one hand, very high concentrations of glutamate must be delivered to postsynaptic receptors to evoke rapid excitatory responses. On the other hand, even rather low concentrations of glutamate, if present tonically, will desensitize those receptors and even kill neurons. This conundrum has been solved by the expression of high densities of glutamate transporters, primarily by astrocytes. Because of their high expression levels and rapid binding kinetics, these transporters aid diffusion in curtailing the glutamate transients that result from exocytosis. In addition, because glutamate uptake has a high coupling ratio to transmembrane ion gradients, ambient extracellular glutamate concentrations are maintained at very low levels.