Differentiation--dependent changes of the nicotinic acetylcholine receptor and other synapse-associated proteins.

Developmentally regulated changes were followed by analyzing the appearance of synapse-associated proteins of the electric organ of Torpedo marmorata. At early stages of development acetylcholine receptor and acetylcholine esterase are distributed diffusely over the myotube surface. With differentiation they become increasingly restricted to the central cell surface. This process occurs before axons contact the electrocytes. As soon as axons begin to contact electrocytes one finds a rapid increase in acetylcholine receptor concentration, which is shortly followed by an increased synthesis of 17 S AChE. The final stages of the synapse formation coincide with increasing amounts of a hydrophobic 6 S AChE and increasing amounts of Mr43000 polypeptides, suggesting that the appearance of these components is linked to the maturation of receptor and synapse function.