QUANTITATIVE SUCCINATE-DEHYDROGENASE HISTOCHEMISTRY .3. VARIATIONS IN HISTOCHEMICAL SUCCINATE-DEHYDROGENASE ACTIVITY IN DIFFERENT CROSS-SECTIONS OF THE SAME MUSCLE-FIBER

The variation in histochemical SDH-activity at different levels in the same muscle fibre was determined in muscle fibre cross-sections both by visual classification and quantitative determination of the formazan-deposits. This work resulted in a confirmation of the earlier micro-biochemical studies of Spamer and Pette (1977, 1979) and Lowrey et al. (1978) that the activity of enzymes of the citric acid cycle is not homogeneously distributed in a muscle fibre over its entire length. In addition it is shown that the observed variations in histochemical SDH-activity strongly interfere with the visual muscle fibre typing. Some of the possible causes for these variations in histochemical SDH-activity (section-thickness, presence of the motor-end-plate) and the implications of these findings for the relation between histochemical characteristics and functional properties of the muscle fibres are briefly discussed. © 1979 Springer-Verlag.