How do synaptic vesicles accumulate glutamate?

In our brain, neurons communicate via neurotransmitters, which trigger electrical signals in downstream neurons by binding and activating specific receptors. Neurotransmitters are released through the fusion of synaptic vesicles, which contain large amounts of neurotransmitters. Scientists from the Institute of Molecular an Cellular Physiology of Forschungszentrum Jülich and the University of South Florida studied how synaptic vesicles accumulate the neurotransmitter glutamate and developed a mathematical model of the synaptic vesicle that describes these processes. The results have now been published in the renowned journal Nature Communications.

The unique computing performance of our brain is based on fast and high frequency communication between neurons. High frequency synaptic transmission requires constant regeneration of synaptic vesicles. For this, immature synaptic vesicles invaginate from the plasma membrane and are filled by specialized neurotransmitter transporters. Vesicles initially contain the same salt solution as the extracellular space, with high concentrations of chloride (Cl-) and sodium (Na+). For glutamatergic synaptic vesicles, chloride ions must be removed in order to effectively enrich the vesicle with glutamate, which is also negatively charged. Both of these tasks are performed by the same protein, the vesicular glutamate transporter. The Jülich scientists used electrophysiological methods to study how this happens in detail.

A press release from Forschungszentrum Jülich. Further information here: https://www.fz-juelich.de/en/news/archive/highlights/2023/how-do-synaptic-vesicles-accumulate-glutamate