Fig. 2

Muscle preparation for histochemical reactions. a. the fresh muscle sample is sectioned following the longitudinal direction of the fibers and small fragments are immediately glutaraldehyde fixed for eventual electron microscopy studies, if necessary; cylindrical fragments are separated to make liquid nitrogen frozen muscle blocks in order to preserve enzymatic functions. b Optimal cutting temperature (OCT) mounting medium is applied on the surface of the previously identified cork. c The muscle fragment is either cooled in isopentane (data not shown) or involved in talcum powder in order to avoid freezing artifacts. d Muscle fragment over cork support. e Liquid nitrogen frozen muscle tissue. f The muscle fragment was frozen in liquid nitrogen and mounted in a cork and a pin. g The muscle fragment was fixed inside the cryostat for the performance of the frozen sections. i The frozen section may be transferred either to a coverslip (photo) or to a glass slide (data not shown). j Coverslip inside reaction dish. k Frozen sections in incubator. l the incubated coverslips are extracted from the coverslip jar to mount the slides for microscopic visualization