CAPILLARY ARCHITECTURE IN THE SKELETAL-MUSCLES IN THE RAT HIND-LIMB

We observed differences in the capillary architecture of the skeletal muscles that have different fiber metabolism. The soleus, the vastus i ntermedius and the tibialis anterior muscles of adult Wistar rats were prepared using two different techniques. Samples for adenosine tripho sphatase (ATPase) staining were prepared following Dubovitz's method, and the distributions of fiber type, Types 1, 2A and 2B, were analyzed . Then, corrosion casts of capillary architecture of these muscles pre pared following Murakami's method were observed with a scanning electr on microscope (SEM) and compared with the fiber distribution. The fibe r type composition of the soleus muscle showed Type 1 (slow-twitch) do minance and that of the vastus intermedius and the tibialis anterior m uscle showed Type 2 (fast-twitch) dominance. The capillaries of the so leus muscle were tortuous, and this was thought to be advantageous for blood supply. In contrast, the capillaries of the vastus intermedius and tibialis anterior muscles had a relatively parallel pattern. Addit ionally, two different patterns of capillary architecture that appeare d to correspond to certain metabolic characteristic of different muscl e fiber types were preserved with corrosion casting. In conclusion, co mparative studies on capillary architecture of the skeletal muscles ar e useful for analyses of its function.