Junctional physiology and motor nerve distribution in the fast adductor muscle of the scallop.

Electrical recordings from single muscle cells in the fast portion of the scallop adductor have revealed a multiterminal distribution of motor nerves. All motor junctions appear to be of the fast designation, and several nerve fibers supply each muscle cell. The muscle fibers, by virtue of common innervation, are grouped into functional motor units. The pattern of innervation in scallops thus shares functional similarities with the motor distribution to skeletal muscle fibers of both vertebrates and arthopods.