Henrique von Gersdorff

Ph.D. (Physics), University of Minnesota, 1989
Ph.D. (Neurobiology), State University of New York, Stony Brook, 1995
Assistant Scientist, Vollum Institute
Joint Assistant Professor, Cell and Developmental Biology

Sensory information is conveyed by neurons specialized to faithfully transmit large amounts of information at high rates. A key event in synaptic transmission is the exocytosis of synaptic vesicles at presynaptic nerve terminals triggered by Ca influx. Direct studies of synaptic terminals have, however, been hampered by their small sizes. Using high time resolution membrane capacitance measurements, we have studied the kinetics of exocytosis, and subsequent membrane retrieval via endocytosis, at retinal synaptic terminals. These giant synapses have compact ribbon-type active zones, and we have found that they contain a large pool of readily releasable synaptic vesicles, suitable for the transfer of high bandwidths of information. Using electrophysiological recordings from infrared visualized brain slices, we are also studying the kinetics of transmitter release at conventional active zone synapses. In particular, we are investigating the mechanisms responsible for synaptic plasticity at a large calyx-type glutamatergic synapse in the mammalian auditory brainstem. We have found that synaptic depression at this synapse has a presynaptic locus that reflects vesicle pool depletion. Paired patch-clamp recordings of the calyx terminal and postsynaptic cell permit us to simultaneously record presynaptic Ca current and excitatory postsynaptic current. This direct access to the terminal allows us to also control the presynaptic intracellular milieu, and to thus study what factors influence synaptic vesicle fusion probability and how presynaptic receptors modulate neuronal output patterns.

von Gersdorff, H. Synaptic ribbons: versatile signal transducers. Neuron 29:7-10, 2001.

Taschenberger, H. and von Gersdorff, H. Fine-tuning an auditory synapse for speed and fidelity: Developmental changes in presynaptic waveform, EPSC kinetics, and synaptic plasticity. J. Neurosci. 20:9162-9173, 2000.

Protti, D.A., Flores-Herr, N., and von Gersdorff, H. Light evokes Ca²⁺ spikes in the axon terminal of a retinal bipolar cell. Neuron 25: 215-227, 2000.

von Gersdorff, H. and Matthews, G. Electrophysiology of synaptic vesicle cycling. Annual Rev. Physiol. 61:725-752, 1999.

To contact Dr. von Gersdorff directly: vongersd@ohsu.edu