SMITHSONIAN SC1  NCE  INFORMATION  EXCHA GE    U.S. DEPARTMENT OF        PROJECT NUMBER
PROJECT NUMBER  00 NOT use this space r  HEALTH EDUCATION AN0 WELFARE
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                         INTRAYURAL RESEARCH PROJECT    201 HL 00017-02 LBG

PER IO0 COVERED

July 1, 1976 through September 30, 1977
TITLE OF PROJECT (80 characters or less)

Acetylcholine Receptors in the Developing Nervous System

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NAMES, LABORATORY AND INSTITUTE AFFILIATIONS, AND TITLES OF PRINCIPAL INVESTIGATORS AND ALL OTHER
PROFESSIONAL PERSONNEL ENGAGED ON THE PROJECT

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PI:    Hiroyuki Sugiyama    Visiting Associate        LBG NHLBI
     Marshall Nirenberg    Chief, LBG               LBG NHLBI

LAG/BRANCH
Laboratory of Biochemical Genetics
SE                  -'
Section on Molecular Biology
I:ISTITUTE AND LOCATION
NHLBI, NIH, Bethesda, Maryland 20014
TOTAL MANYEARS:             PROFESS I ON AL:
1.6                  1.3

OTHER:
      0.3

CHECK APPROPRIATE BOX(ES)
z (a) HUMAN SUBJECTS        O (b) HUMAN TISSUES

g (al) MINORS 0 (a2) INTERVIEWS
SUMMARY OF WORK (200 words or less - underline keywords)

8 (c) NEITHER

  The goal of this project is to define the properties of muscarinic and
nicotinic acetylcholine receptors and acetylcholinesterase during development
of chick embryo retina.  Thus far we have elucidated (1) the specificity and
affinities of muscarinic and nicotinic acetylcholine receptors for receptor
activation and antagonists, (2) the number of receptors were defined as a
function of developmental age of the retina, and (3) the location of nicotinic
and muscarinic receptors within the retina was determined.

PHS-6040
(Rev. I O-76)


ZOl HL 00017-02 LBG

Project Description:

   Objectives:  The objectives are to define the biochemical properties of
acetylcholine receptors before and after synaptogenesis in the retina.

   Major Findings:  Neurons dissociated from chick embryo retina and main-
tain d in vitro were found to reaggregate and form, in vitro,
x lo5 --                              approximately 1
    synapses per mg of protein.  Three types of synapses and several subtypes
were identified which closely resemble those of the intact retina.

  Chick embyro retina was found to be a rich source of both muscarinic and
nicotinic acetylcholine receptors.  Both muscarinic and nicotinic acetylcholine
receptors are synthesized before synapses appear in the retina; however, during
development, nicotinic acetylcholine receptors become associated predominantly
with neurites in the synaptic layers of the retina.  Muscarinic acetylcholine
receptors also were found to localize in the inner synaptic layer of the
retina, but the receptor distribution differs from that of nicotinic acetyl-
choline receptors.  The properties of muscarinic acetylcholine receptors were
determined at different developmental ages and were compared with the proper-
ties of muscarinic inhibitory and excitatory receptors of neuroblastoma and
hybrid cells.

  Significance to Biomedical Research:  Information was obtained which serves
as a basis for further studies on the role of acetylcholine receptors in
synapse formation.

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Proposed Course: Further studies on receptor properties are planned: