Developmental expression of dystrophin on the rat myocardial cell membrane.

The Duchenne muscular dystrophy gene product, dystrophin, is expressed on the cell membrane of skeletal and cardiac muscles. We examined the developmental time course of dystrophin expression in the rat ventricular myocardium. Dystrophin was immunohistochemically undetectable on the 15th embryonic day, but a small amount was expressed on the cell membrane on the 17th embryonic day. The amount increased during the perinatal period reaching adult level at 2 weeks after birth. These findings were supported by immunoblot analysis. Chemical sympathectomy in newborn rats by 6-hydroxydopamine (prevention of innervation) had no detectable influence on myocardial dystrophin expression at 2 weeks after birth. Our results show that dystrophin lining on the rat myocardial cell membrane increases during the perinatal period, and that this process is little influenced by the development of sympathetic innervation.