[Experimental and pathological changes of the neuromuscular junction]

The objective of our study was to investigate the cellular communication between the axon and its postsynaptic targets in the synapse. We used the neuromuscular junction (NMJ) model, which is a highly specialized structure between the nerve, the muscle, and the Schwann cell terminal where the motor neuron orders the muscle to contract. We used experimental models of motor nerve reimplantation in a denervated muscle to determine whether 1) the formation of new NMJ could participate in reinnervation of the muscle necessary to contraction or 2) the blockage of neurotransmitter release using botulinum toxin could be compensated by the formation of new NMJ. We also studied human genetic diseases that affect neuromuscular transmission--congenital myasthenic syndromes--to identify the mutations in the genes coding for synaptic molecules and to analyze the compensatory processes involved in NMJ dysfunction so that muscle contraction can occur in these conditions.