[Attempts to enrich and to solubilize the muscarinic acetylcholinereceptor from bovine caudate nucleus (author's transl)]

Abstract

Neuronal membranes of postsynaptic origin twofold enriched in acetylcholinesterase, muscarinic acetylcholinereceptor and (Na+/K+)-ATP-Phosphohydrolase, proteins associated with cholinergic nerve excitability, were prepared with yields between 60 and 75% from bovine caudate nucleus. On subfractionation of these membranes an additional twofold enrichment of the mentioned proteins is achieved in different subfractions. SDS-gradient gel electrophoresis shows that these subfractions have slightly different polypeptide compositions. Neuronal membranes of presynaptic origin on the other hand, prepared from purified synaptosomes, possess only small amounts of the mentioned proteins, showing no enrichment with respect to the homogenate. Solubilization of acetylcholinesterase with 1 M NaC1 as well as of muscarinic acetylcholinreceptor with 2 M NaC1 does not succeed. These proteins are therefore not solely bound by ionic forces to the isolated membranes from bovine caudate nucleus.