***** seminarMLから情報転載 *****


タイトル:Diffusional barriers to biochemical signals in neurons
     From synapses to dendrites

演者:Fidel Santamaria&s_comma; PhD
Department of Biology&s_comma; The University of Texas at San Antonio

要旨:The spread of biochemical signals is not only important to sustain the
normal metabolic activity of neurons but it is crucial for neuron-specific
function such as synaptic plasticity. In this talk I will present
experimental and computational results showing that the intricate structure
of neurons severely affects the spread of chemical signals. I will address
three specific examples spanning a wide range of spatial scales&s_comma; from
diffusion of biochemical signals in dendritic trees to molecular aggregation
in synapses. At the largest spatial scale&s_comma; I will show how the structure of
dendritic trees affects diffusion of molecules in the cytosol. In this case
we find that dendritic spines act as molecular traps for molecules moving
along the dendrites of cerebellar Purkinje and hippocampal pyramidal cells.
The second example shows initial evidence that the cytosolic structure of
neurons&s_comma; composed of cytoskeleton and macro-molecules&s_comma; is different between
dendrites and soma. I will introduce a relatively new technique called
fluorescence correlation spectroscopy that we use to measure the diffusional
environment of cells at sub-microscopic levels in combination of two-photon
microscopy. The third example will be modeling work suggesting a strong
influence of the molecular structure of the post-synaptic density in
determining the homeostasis of glutamate receptors in synapses. I will end
by discussing the consequence of all these mechanisms in the activation of
long term depression&s_comma; a cellular model of learning and memory in Purkinje
cell synapses.

日時:平成21年2月23日(月) 15:00~16:00