INCREASED EXPRESSION OF DYSTROPHIN, BETA-DYSTROGLYCAN AND ADHALIN IN DENERVATED RAT MUSCLES

To evaluate a potential regulatory role of the nerve, the distribution and expression of dystrophin, of beta-dystroglycan (43DAG) and adhali n (50DAG), two of the dystrophin-associated proteins and utrophin (dys trophin related protein or DRP) were studied in rat muscles after 2 we eks of denervation. We found that dystrophin, beta-dystroglycan and ad halin were overexpressed in denervated muscle, whereas utrophin did no t increase and was found only in the post-synaptic membrane. The study of the distribution of dystrophin in the sarcolemma of single muscle fibres indicates that the molecular organization of dystrophin was mai ntained after denervation. Dystrophin in addition of forming a scaffol d around the fibre was found around the clusters of AChR that reappear ed in the extra-synaptic membrane after denervation. Also beta-dystrog lycan colocalises at these clusters. These results suggest that the in crease in dystrophin, beta-dystroglycan and adhalin is correlated with the reappearance of AChRs in the extra synaptic membrane.