Distribution of caveolin in the muscle spindles of human skeletal muscle.

The aim of the present study was to demonstrate the location of the different members of the caveolin (cav) family in human muscle spindles. Twenty spindles of three human muscles (vastus medialis, ischiocavernosus, bulbospongiosus) from 12 cadavers were immunohistochemically stained for cav-1, cav-2, and cav-3, and the equatorial and polar regions evaluated. All layers of the outer and inner spindle capsule and all blood vessels within the spindle stained for cav-1 and cav-2. In the muscle spindle, intrafusal muscle fibres stained selectively for cav-3, but with a patchy appearance. Caveolinopathies may therefore also include changes in muscle spindle function.