Demonstration of creatine kinase in myocardial and skeletal muscle using the semipermeable membrane technique.

The histochemical method as described by Sjövall (1967) for the detection of creatine kinase activity in myocardium and skeletal muscle has been modified by the introduction of a semipermeable membrane method. With this technique a semipermeable membrane is interposed between incubating solution and tissue sections preventing diffusion of the enzyme into the medium during incubation. A very high enzyme activity was demonstrated along myofibrils and probably also in mitochondria. Addition of ZnCl2 or 2,4-dinitrofluorobenzene to the incubation medium prevented the production of formazan, confirming the specificity of the staining reaction. Creatine kinase activity was observed in both white (type II) and red (type I) skeletal muscle fibres without notable difference in level of activity.