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12635 E. Montview Blvd., Suite 270
Aurora, CO 80045
P: (720) 859-4149
F: (720) 859-4158
Glutamate Vesicle Filling and Release Probability
Investigators: Lauren Mamer, the Ohio State University College of Medicine & Melissa Herman, PhD, Charité University of Medicine
Mentor: Christian Rosenmund, PhD, Charité University of Medicine
Abstract: Glutamate is the most common excitatory neurotransmitter in the brain, and is responsible for a wide range of functions. In addition to its ubiquity in the brain, it is becoming an increasingly important drug target for neuropsychiatric therapies and it is therefore critical to understand how glutamate is released and trafficked in the brain. Like all neurotransmitters, glutamate is released in an unreliable manner at the synapse. The exact determinants of the probability of release at a synapse remain incompletely understood. Our hypothesis is that the filling state of vesicles is a key determining factor for release probability. In these experiments we examined this hypothesis using a derivative of Trypan Blue to inhibit the function of the glutamate vesicle filling protein VGlut and detected the release probability of these neurons using the synaptophysin-pHluorin imaging technique. We first established the effectiveness and selectivity of our inhibitor for glutamatergic neurons and then used the synaptophysin-pHluorin technique to visualize cells with these empty vesicles. In the inhibited group, we saw a decrease in the total change in fluorescence triggered by 300 action potentials at 20 Hz compared with the change in fluorescence seen in control cells during the same stimulus. This result supports our hypothesis that empty vesicles have a lower release probability, and these results warrant further investigation. In addition, our characterization of the inhibitor of VGlut may lead to further information about the function of the VGlut transporter and the dynamics of the glutamatergic synapse.
Last Updated: 1/7/14
Updated on January 8, 2014.