The body harbors a complex muscle system, in which individual muscles can be identified by their size, position, shape, function, and attachments. The skeletal muscles are striated and voluntary, highly specialized muscles, which attach to bones via tendons, have a specific anatomical position and innervation, and move the skeleton. Cardiac muscle is of a unique kind, striated and of involuntary type. The smooth muscle is also involuntary, and moves the bowel, modifies vessels, and constricts the bladder, to name just a few of its functions. By muscle diseases, one usually means diseases affecting the skeletal muscle, and experimental research on this muscle type is the focus of this chapter.
Diseases of muscle may result from a range of defects, from developmental defects to those in structural backbone proteins and energy metabolism. Research clarifying the nature of defects in muscle diseases has been a valuable source of information for understanding normal muscle function. Experimental muscle models can be created to study the normal function of a protein, or to study the effect of a gene mutation to clarify disease pathogenesis. Alternatively, interesting phenotypes may have arisen spontaneously in experimental animal lines, and their characterization may bring new knowledge of muscle function and diseases. Most experimental procedures concerning muscle diseases are common routine techniques of molecular biology and genetics. Therefore, in this chapter, we have concentrated on introducing those aspects of experimental muscle research that are specific for the tissue and its diseases.