Effect of heterotopic innervation on the development of synaptic pattern in chick embryo muscles.

Heterotopic transplantations of fragments of neural tube have been performed in the chick embryo on stage 22 somites. Brachial motor centres were replaced by a posterior segment of spinal cord. As a result, synpatic patterns of Posterior Latissimus Dorsi (PLD) and Anterior Latissimus Dorsi (ALD) were modified : PLD exhibited numerous muscle fibers with a distributed innervation and ALD fibers had a large variability of intersynaptic lengths. Histochemical properties of myofibrillar ATPase activity in ALD and PLD muscles were close to those in controls, in spite of change in the innervation supply.