Optical diffraction of the Z lattice in canine cardiac muscle.
Optical diffraction patterns from electron micrographs of both longitudinal and cross sections of normal and anomalous canine cardiac Z bands have been compared. The data indicate that anomalous cardiac Z bands resembling nemaline rods are structurally related to Z bands in showing a repeating lattice common to both. In thin sections transverse to the myofibril axis, both electron micrographs and optical diffraction patterns of the Z structure reveal a square lattice of 24 nm. This lattice is simple at the edge of each I band and centered in the interior of the Z band, where two distinct lattice forms have been observed. In longitudinal sections, oblique filaments visible in the electron micrographs  correspond to a 38-nm axial periodicity in diffraction patterns of both Z band and Z rod. We conclude that the Z rods will be useful for further analysis and reconstruction of the Z lattice by optical diffraction techniques.
D000818:Animals; D004285:Dogs; D007511:Ischemia; D008954:Models, Biological; D009206:Myocardium / Q000648:ultrastructure*; D009210:Myofibrils / Q000648:ultrastructure; D055095:Optics and Photonics