EN
Reinnervation observed in early stage of amyotrophic lateral sclerosis (ALS) is a compensatory mechanism for motoneuron loss. Since survival motor neuron (SMN) protein could be involved not only in neuroprotection but also in the transport of mRNAs in motoneuron axons, we examined its immunoexpression in anterior horn motoneurons of ALS patients with reinnervation in EMG. SMN immunolabel was observed in neuron cytoplasm and neurities but it was particularly intense in enlarged Nissl granules. This finding may mirror increased synthesis of the protein in rough endoplasmic reticulum being not only an attempt of motoneuron to selfprotection but also necessary for nerve sprouting. Study supported by the Ministry of Sciences and Higher Education grant NN 401 014 640.