title: Acetylcholine release from proteoliposomes equipped with synaptosomal membrane constituents.
abstract: A lyophilized presynaptic membrane powder prepared from Torpedo electric organ synaptosomes was incorporated into liposomes. These proteoliposomes had a large internal volume. The P and E faces of their membrane showed particles which were comparable to the presynaptic membrane ones. The synaptosomal ecto-esterase activity was also incorporated. A large amount of acetylcholine could be entrapped in the proteoliposome which became permeable to acetylcholine in the presence of calcium. Acetylcholine was released in preference to choline. The calcium-induced acetylcholine release depended on the incorporation of a presynaptic membrane constituent. Proteoliposomes prepared from postsynaptic membrane powders gave a much slower acetylcholine efflux. The protein pattern of presynaptic and postsynaptic membrane proteoliposomes were compared.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D004557:Electric Organ / Q000378:metabolism; D005614:Freeze Fracturing; D007700:Kinetics; D008081:Liposomes; D008854:Microscopy, Electron; D011510:Proteolipids / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*; D014101:Torpedo
chemical_list: D008081:Liposomes; D011510:Proteolipids; C020485:proteoliposomes; D000109:Acetylcholine