Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 12 March 1971:
Vol. 171. no. 3975, pp. 963 - 971
DOI: 10.1126/science.171.3975.963
Prev | Table of Contents | Next

Articles

Molecular Biology of Synaptic Receptors

Eduardo De Robertis 1

1 The Instituto de Anatomía General y Embriología, Facultad de Medicina, Universidad de Buenos Aires, Argentina

A special proteolipid (a hydrophobic protein) has been extracted and purified from nerve-ending membranes and total particulate matter of gray areas of the central nervous system. Such a proteolipid shows a high affinity for binding d-tubocurarine, serotonin, and atropine and has been called receptor proteolipid. The interaction of this proteolipid with atropine sulfate was studied with light scattering and polarization of fluorescence. The changes observed, which follow a cooperative type of curve, were attributed to the aggregation of the proteolipid macromolecules. Such a phenomenon was then observed under the electron microscope.

A receptor proteolipid having a high affinity for binding acetylcholine, hexamethonium, and other cholinergic drugs was isolated and purified from electric tissue of fishes and from electroplax membranes. Such a proteolipid was also extracted from membranes from which acetylcholinesterase had been removed, and it was concluded that this enzyme and the receptor proteolipid are two different macromolecules. A high affinity binding site with a dissociation constant of K1 equal to 10-7 and about ten sites with K2 equal to 10-5 were recognized in the receptor proteolipid.

Under the electron microscope the receptor proteolipid of brain appears as a rod-shaped macromolecule which may assume paracrystalline arrays with 10-8 molar atropine sulfate. Similarly the receptor proteolipid from electric tissue and from skeletal muscle may form paracrystalline arrays under the action of acetylcholine and hexamethonium.

A model of the cholinergic receptor based on the properties of the proteolipid is presented. Preliminary work indicates the possibility of obtaining a biophysical response to acetylcholine when the receptor proteolipid is embedded in artificial bilayered lipid membrance.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Facets of the Structures of Acetylcholine Receptors from Electrophorus and Torpedo.
A. Karlin, C. L. Weill, M. G. McNamee, and R. Valderrama (1976)
Cold Spring Harb Symp Quant Biol 40, 203-210
   Abstract »    PDF »
Some Structural Properties of the Cholinergic Receptor Protein in Its Membrane Environment Relevant to Its Function as a Pharmacological Receptor.
J.-P. Changeux, L. Benedetti, J.-P. Bourgeois, A. Brisson, J. Cartaud, P. Devaux, H. Grunhagen, M. Moreau, J.-L. Popot, A. Sobel, et al. (1976)
Cold Spring Harb Symp Quant Biol 40, 211-230
   Abstract »    PDF »
Altered Cell Membranes in Creutzfeldt-Jakob Disease: Microchemical Studies.
N. H. Bass, H. H. Hess, and A. Pope (1974)
Arch Neurol 31, 174-182
   Abstract »    PDF »
Acetylcholine Receptors: Number and Distribution at Neuromuscular Junctions in Rat Diaphragm.
D. M. Fambrough and H. C. Hartzell (1972)
Science 176, 189-191
   Abstract »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)