Abstract

Glutamine is the most abundant amino acid in the brain’s extracellular fluid. It is important for protein and nucleotide synthesis, and it has been suggested to play a role in the generation of the neurotransmitters glutamate and GABA . By using electrophysiological and fluorescent imaging techniques, we aim to discover if and how glutamine is involved in controlling the levels of neurotransmission in the mammalian brain. We have recently shown that postsynaptic neurones are able to transport glutamine into the cell body and our preliminary data demonstrate, for the first time, that presynaptic terminals are also capable of direct glutamine import. Additionally, we hypothesize that glutamine is released from glial cells at the synapse. In support of this, data recorded from synapses and associated glia indicate that neuronal activation results in glial glutamine release, in a very rapid and highly coupled manner. While we have identified some of the transporters that mediate the release and uptake of glutamine at the synapse, some processes still remain elusive. These exciting data give an insight into the mechanisms that fast synapses use to sustain their levels of neurotransmitter supply, which is vital for maintaining synaptic communication.