Project Details


This research proposal is concerned with a study of synaptic
mechanisms in the outer plexiform layer of the vertebrate retina.
Pre-and postsynaptic function will be examined separately by
using freshly isolated retinal neurons and synape formation
between mature neurons will be examined in long term cultures of
dissociated retinal cells. 2) Presynaptic transmitter release by
exocytosis can be quantified with the rapid freezing technique in
amphibian and mammalian rod cells. This approach will yield
information on the rate of synaptic vesicle release in the dark and
during the light response. Synaptic vesicle membrane
recyclingwill be followed by pulse labeling with ultrastructural
lables and rapid freezing. By combining these techniques it will
be possible to identify the organelles which retrieve synaptic
membrane, regenerate synaptic vesicles, and transport membrane
to the cell body. 2) the role of Ca++ in synaptic activity and
phototransduction will be explored by identifying the Ca++-
sequestrating organelles of active photoreceptors with rapid
freezing and freeze substitution. 3) Cholinergic receptors will be
localized on first and second order neurons with radiolabeled
ligands and light and electron micorscopic autoradiography. Using
competitive ligands it will be possible to selectively visualize the
binding sites of muscarinic subtypes and determine their binding
affinities both for specific cell types and for parts of neurons.
and 4) The fate of denervated presynaptic active zones and the
specificity of newly formed synapses will be determined with
morphological and patch-clamp examination of selected pairs of
retinal neurons maintained in vitro. These experiments on
synaptic function answer general biological questions concerning
secretion and cytoplasmic organelle function; they explore how
visual information is communicated by photoreceptors to second
order neurons; they examine the possible cholinergic interactions
in the outer plexiform layer; and they test the ability of adult
neurons to regenrate. In the long term, it is hoped that they will
provide a basis for the use of cell culture techniques in studies of
photoreceptor cell biology and synaptic interactions. The
continued analysis of the normal function of visual cells is
essential in order to understand the alterations which occur in
retinal and choroidal disease processes. For the protoreceptor,
this may be especially important since rod/cone degeneration is a
primary defect in a number of retinal disorders whose etiology is
essentially unknown.
Effective start/end date12/31/896/30/98


  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute
  • National Eye Institute


  • Medicine(all)
  • Ophthalmology
  • Cell Biology


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