Biochemical and cytochemical comparison of surface membranes from normal and dystrophic chickens.

Cytochemical and biochemical characteristics of the surface membrane components of avian dystrophic muscle were examined. A Mg2+- or Ca2+-activated ("basic") adenosine triphosphate (ATPase) was localized cytochemically in fixed, intact dystrophic muscle slices in a medium containing Mg2+ or Ca2+, adenosine triphosphate (ATP), and 1 microM free Pb2+ to capture enzymatically released phosphate ions. Electron-dense staining precipitates were found to be associated with the plasmalemma and its tortuous invaginations, and the transverse components of the T-system membrane and its associated proliferated networks. Enzymatic analysis of microsomal fractions isolated from 7-day-old and 90-day-old normal and dystrophic muscle showed a complex behavior. Specific activity of "basic" ATPase decreased with maturity in normal and dystrophic animals. The specific activities of the surface membrane associated enzymes, leucyl beta-naphthylamidase, adenylate cyclase, and guanylate cyclase, remained at various elevated levels in the mature dystrophic animals, in contrast to the normal muscle, which showed decreases in the specific activity of all three enzymes with maturation. The persistent high levels in some but not all enzyme activities in 90-day-old dystrophic muscle indicates a complicated developmental pattern in the dystrophic chicken muscle.