Thrombin reduces MuSK and acetylcholine receptor expression along with neuromuscular contact size in vitro.

In the course of studies on thrombin and its inhibitor(s) in synaptic plasticity, we addressed the question of their roles in the formation of neuromuscular junctions (NMJ) and used a model of rat neuron-myotube cocultures. We report that the size of acetylcholinesterase (AChE) patches used as a marker of neuromuscular contacts was decreased in the presence of either thrombin or SFLLRN, the agonist peptide of the thrombin receptor PAR-1, whereas it was increased with hirudin, a specific thrombin inhibitor. In an attempt to relate these neuromuscular contact size variations to molecular changes, we studied muscle-specific tyrosine kinase receptor (MuSK), acetylcholine receptor (AChR) and rapsyn expression in the presence of thrombin.

Preparation of isolated human muscle fibers: a technical report.

The aim of this study was to develop a technique to culture satellite cells from isolated intact fast or slow human muscle fibers. Previous studies have been carried out on small rodent muscles where the fibers run from tendon to tendon, but this is the first description of the modification of this technique for much larger human muscles. We have demonstrated that the human muscle fibers are in fact segmental, and we have also shown that it is possible to obtain very pure satellite cell cultures.