The effect of denervation on a cholinergic hydrophobic protein isolated from rat diaphragm

Hydrophobic lipoproteins (i.e. proteolipids) from rat diaphragm were separated by column chromatography with Sephadex LH20. A protein peak 2-R, eluted with chloroform, was found to bind 14 C-acetylcholine and other cholinergic ligands. Following denervation there was an increase in this protein peak which was accompanied by an increase in the binding for 14 C-acetylcholine. This effect was more marked in the non-innervated portion of the muscle. The large amount of protein and of molecules of ligand bound to peak 2-R favors the view that in normal skeletal muscle most receptors are in a non-reactive form and that they may be reactivated by denervation or by extraction with organic solvents.