“…Similar results are obtained when the nerve supply to a muscle is crushed or divided and sutured (Tello, 1907; Gutmann & Young, 1944;Csillik & Savay, 1959), although in these cases it has been suggested that the regenerating nerve is simply led to the old end-plates by growing down the endoneurial tubes of the peripheral nerve stump (Gutmann & Young, 1944). There is also histological evidence of reinnervation of endplates after implantation of the reinnervating nerve directly into the denervated muscle (Shukla & Aitken, 1963;Saito & Zacks, 1969), although many synapses are also found away from the old end-plate region, especially close to the site of the implant (Koenig, 1963;Guth & Zalewski, 1963; Gwyn & Aitken, 1966;Fex & Jirmanova, 1969); however, it is uncertain to what extent these ectopic end-plates are due to injury (Miledi, 1963) or atrophy of the muscle (Aitken, 1950;Saito & Zacks, 1969). In the present work, the site of synapse formation in spontaneously reinnervated mammalian muscles has been determined by electrophysiological, histological, and ultrastructural techniques and it has been shown that the end-plate regions of mammalian muscle fibres are preferentially reinnervated.…”