Dynamic 3-D modelling of the synaptic environment: The roles of transporters in controlling receptor activation and water transport

Prevention and cure of neurological diseases are hampered by a lack of knowledge of the underlying pathogenetic mechanisms which involve a complex system of transporter proteins. The primary objective of this proposal is to uncover how transporters limit activation of brain neurotransmitter receptors. To achieve this, it is not sufficient to generate qualitative data on transporter and receptor localizations. It is necessary to determine the numbers of the various protein molecules at different locations within and around synapses. Then this information must be analyzed using super computer simulation of neurotransmitter diffusion in dynamic 3-D models of cubes of brain tissue. The models must take into account protein densities, localizations, affinities , and other relevant properties like ion channel conductances and associated water transport. We will begin the development of these advanced models, and we will also provide the quantitative data (molecules per square micrometer membrane) needed to mode l the roles of all the transporter proteins with affinity for glutamate and GABA. One transgenic mouse line will be produced to address an important questions related to the model: the functional importance of glutamate transporter EAAT2 in synaptic term inals. This project combines expertise in computer simulation, brain ultrastructure, membrane protein purification, molecular biology, water transport and electrophysiology in order to achieve the ambitious goal.