Utrophin is lacking at the neuromuscular junctions in the extraocular muscles of normal cat: artefact or true?

Extraocular muscles (EOM) are typically spared in Duchenne muscular dystrophy. We hypothesized that this might be due to different patterns of utrophin expression. The expression of utrophin was examined in EOM of normal cats using immunohistochemical methods and Western blot. For detecting acetylcholine receptors (AChR), we used alpha-bungarotoxin. Surprisingly, alpha-bungarotoxin failed to stain the AChR and no expression of utrophin could be detected at the neuromuscular junctions. Our study could indicate that the expression of utrophin is dependent on the structure of the AChR.