主题：Endocytic Recycling Pathway Determines the Properties of Neurotransmitter Release
报告人：Prof. Robert Edwards, School of Medicine, University of California San Francisco
In the course of studying glutamate corelease by dopamine neurons, we found that the two transmitters signal with different short-term kinetics: the glutamate response depresses more rapidly than the dopamine. Although this might reflect differences in the properties of glutamate and dopamine receptors, we found that release of the two transmitters couples to different presynaptic Ca++ channels. The direct analysis of individual release events by imaging shows that vesicles storing glutamate and dopamine behave differently even when located at the same presynaptic bouton. The two synaptic vesicle populations also appear to form through different endocytic mechanisms. In contrast to glutamate vesicles which have been shown to recycle dependent on clathrin and its adaptor protein AP-2, monoamine vesicles depend on the related but distinct adaptor AP-3. Thus, different endocytic pathways produce synaptic vesicles with different transmitter content and release properties, with important implications for organization of the nerve terminal and for the processing of information.