Electron cytochemistry of acetylcholinesterase in the neuromuscular junction during ontogenesis

Electron histochemical studies were performed on neuromuscular junctions of the diaphragm in early postnatal states of development in rat by means of the acetylthiocholine technique. Presynaptic AChE appears to be derived from perikaryal sources, carried along by means of axonal transport mechanisms. Postsynaptic AChE is synthesized in the sarcotubular system of the underlying muscle fiber and within the perinuclear and endoplasmic reticulum of fundamental cells. Distribution of AChE synthesizing loci parallels with that of acetylcholine sensitive areas.