SN1 Catalyzes Transport of Glutamine Across Müller Cells in Retina
- 146 Downloads
High-affinity glutamate (Glu) transporters localized on Müller cell membranes transport synaptically released Glu into these cells from the extracellular side. Müller cells, similar to most glial cells in the nervous system, generate glutamine (Gln) from Glu using the enzyme glutamine synthetase. Although it has been postulated that Gln is transported from these Müller cells to replenish synaptic Glu, little is known about the identity or properties of the Gln transporter. We investigated the Gln transport mechanism in Müller cells dissociated from retinae of tiger salamander (Ambystoma tigrinum) using three different approaches: intracellular pH (pHi) measurements, whole-cell voltage-clamp, and immunocytochemistry.