Substrains of Inbred Mice Differ in Their Physical Activity as a Behavior
Figure 3
Muscle metabolic adaptations to wheel running in BALB/c AnNCrl mice. Histochemistry for NADH transferase activity highlights oxidative (O), intermediate (I), and glycolytic (G) fibers; that is, muscle fibers that are rich (O or I) and poor in mitochondrial content, respectively. The inset at higher magnification allows to differentiate among the three types of fibers. O + I fibers were collectively considered as rich in NADH transferase (NADH-TR + fibers). Representative photomicrographs of the TA of (a) control, nonexercised mouse and (b) a mouse following nineteen days of exercise. The percentage of NADH-TR+ fibers was quantified in replicate, after no (0), five (5), or nineteen (19) days of wheel running.
