NSF Award
0080007
008007<br/>Fleck<br/><br/>Cell-cell signaling in the nervous system involves the regulated release of chemical neurotransmitters at specialized synaptic contacts. The principal excitatory neurotransmitter in the mammalian brain is glutamate. Yet the methods available to measure glutamate are indirect and insufficient to study its release in real time or at individual release sites. This proposal seeks to develop a reliable, quantitative, and direct method to measure the release of glutamate during synaptic transmission. Highly selective glutamate sensitive proteins will be employed that generate a measurable current upon glutamate binding. The proteins have been cloned, genetically engineered to enhance their fidelity of signal transduction, and will be incorporated into a biosensor probe. Studies are proposed to test the spatial and temporal limits of detection by such probes while measuring the variability of 'quantal' packets of glutamate, perhaps a few thousand molecules, as they are released during synaptic activity. If successful, these studies will provide a means to address previously intractable questions of synaptic physiology. <br/>Glutamate release is broadly involved in nervous system function and is highly regulated. Developmental and use-dependent changes in the strength of glutamate transmission are important for synapse maturation, learning and memory. Dysregulation of glutamate transmission is implicated in cognitive-memory impairments, epilepsy, affective disorders, and neurodegenerative disease. Therefore, it is important to advance our understanding of the process and regulation of glutamate release.
