Fig. 7. Sarcolemmal focal adhesion kinase (FAK) immunoreactivity in muscle fibres during the slow- to fast-twitch transformation. Sarcolemmal FAK immunoreactivity (A, FAK antiserum A-17; B, control reaction) and fibre type (C, fast myosin) were determined on consecutive cryosections of soleus muscle 10 months after cross-reinnervation (X-SOL) with the nerve supply of the fast-twitch extensor digitorum longus muscle. The fibre types are indicated. Scale bar, 100 µm.