AJP - Heart and Circulatory Physiology, Vol 248, Issue 3 297-H304, Copyright © 1985 by American Physiological Society
Measurements on the internal structure of freeze-fractured cardiac plasma membrane
L. Kordylewski, T. Karrison and E. Page
We describe a quantitative analysis of the internal structure of cardiac
plasma membranes freeze fractured in situ, including the P-face particle
density (lambda), the P-face particle diameter (d), the percent of fracture
face area occupied by particles (Ap), and the spatial distribution of
particles (random, clustered, or ordered). This analysis has been applied
to seven sheep hearts to compare the plasmalemmal internal structures in
ventricular and atrial myocytes and Purkinje strands of the same hearts and
also to myocytes of frog, chicken, rabbit, and rat ventricles (to compare
internal plasmalemmal structure of different vertebrate classes).
Measurements were made on tissues conventionally prepared for freeze
fracture by glutaraldehyde fixation and cryoprotection. We found that, in
the same sheep hearts, lambda and Ap for ventricular plasmalemma
significantly exceeded those for atrial plasmalemma and that the
distribution of atrial P-face particles was more clustered than that for
ventricle. d and Ap for frog ventricular plasmalemmal P-face significantly
exceeded values for some of the other vertebrates.
