TENASCIN IS PRESENT IN HUMAN MUSCLE-SPINDLES AND NEUROMUSCULAR-JUNCTIONS

We used immunocytochemistry to investigate the presence of tenascin, a n-extracellular matrix glycoprotein with very restricted tissue distri bution, in human skeletal muscle. Tenascin was found in a short segmen t of the muscle spindle fibres, in the equatorial region where the sen sory endings are found, and in the outer layers of the spindle capsule . Tenascin was also found in the neuromuscular junctions of the extraf usal fibres. The close spatial relationship between tenascin and both sensory and motor nerve endings shown here suggests that this glycopro tein is of functional importance in adult nerve-muscle contacts in hum an skeletal muscle.