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?OJECT NUMBER t   INFORMATION EXCHANGE
      00 NOT use this space)      U.S. DEPARTMENT OF       PROJECT NUMBER
                         HEALTH EOUCATION AND WELFARE
                  &BLlC HEALTk SERVICE
                                NOTICE Of
                         INTRAYURAL RESEARCH PAOJECT     zol HL 00017-01 LBG


`ERIOD COVEREO

July 1, 1975 through June 30, 1976
ITLE OF PROJECT (80 characters or less)

Acetylcholine Receptors in the Developing Nervous System

AMES, LABORATORY AND INSTITUTE AFFILIATIONS, AND TITLES OF PRINCTPAL INVESTIGATORS ANO ALL OTHER
`ROFESSIONAL PERSONNEL ENGAGED ON THE PROJECT

PI:  Marshall Nirenberg          Chief, LBG      LBG NHLI
   Hiroyuki Sugiyama            Research Associate   LBG NHLI

OOPERATING UNITS (if any)

None

ABJilRpGH
a aratory of Biochemical Genetics
ECTION

Section on Molecular Biology
NSTITUTE AND LOCATION

NHLI, NIH, Bethesda, Maryland 20014
OTAL MANY EARS:            PROFESSIONAL:           OTHER:
1.6                  1.3              .3
UMMARY OF WORK (200 words or less - underline keywords)

The goal of this project is to define the properties of muscarinic and
nicotinic acetylcholine receptors of chick embryo retina before and after
synaptogenesis in the retina.  Thus far we have elucidated (1) tha
specificity and affinities of muscarinic and nicotinic acetylcholine
receptors for cholinergic agonists and antagonists, (2) the number of
receptors were defined as a function of developmental age of the retina,
and (3) the location of nicotinic receptors within the retina was determined.

t'HS-bUQU
(12-75)


ZOl Hf. 00017-01 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
maintained in vitro were found to reaggregate and form;in vitro,
            c-
1 x 10' synapses per mg of protein.                     approximately
                      Three types of synapses and several
subtypes were identified which closely resemble those of the intact retina.

Chick embryo 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 as-
sociated predominantly with neurites in the synaptic layers of the retina.
The properties of muscarinic acetylcholine receptors were determined at
different developmental ages and were compared with the properties of
muscarinic inhibitory and excitatory receptors of neuroblastoma cells.

Significance to Biomedical Research:  This study gives fundamental
information and serves as a basis for further studies on the role of this
receptor protein in synapse formation.

Proposed Course:  More detailed studies of synaptogenesis and receptor
properties are planned.

Publications:

1.  Vogel, Zvi and Nirenberg, Marshall:  Localization of acetylcholine
receptors during synaptogenesis in retina.. Proc; Natl. Acad. Sci. USA, In
Press.

2.  Vogel, Zvi, Daniels, Mathew P. and Nirenberg, Marshall:  Synapse and
acetylcholine receptor synthesis by neurons dissociated from retina. 'Proc.
Natl. Acad. Sci., USA, In Press.

3.  Gouras, P., Chader, G., Enrigues, N. and Gibbons, R.G.: Calcium-induced
spikes in cultures pigment epithelium of chich retina.  Invest. Ophthalmol.
15: 62-64, 1976.
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