RESUMO
The effects of chronic diazepan (D) treatment and exercise training on total body mass (TBM), microsomal protein yield (MPY), calcium uptake by fragmented sarcoplasmic reticulum (SR), muscle fibre cross-sectional area, and both PFK and SDH activities were investigated in the tibialis anterior (TA), soleus (Sol), and plantaris (Plt) muscles of 50 male albino Sprague-Dawley rats. Rats were assigned randomly to control (C), sprint-trained (S), or endurance-trained (E) groups. Training was of 12 weeks duration. One-half of each group received daily intraperitoneally D doses of 5 mg kg(-1) of TBM. Exercise reduced TBM (p<0.05); increased the relative BM of the TA (E=2.02+0.02, p<0.01) and Plt (E=1.15+0.02, p<0.01; S=1.13+0.03, p<0.01), as well as the Ca++ uptake of the Sol SR (C=0.08+0.02, E=0.16+01, p<0.05). MPY was elevated in S-Sol (C=1.12+0.6, S=1.52+0.1, p<0.01). Delevated Sol MPY as well as TA PFK. S-trained animals had lower mean fibre areas than the E-trained (D-treated and untreated) animals. The elevated relative masses of TA and Plt are explained by a decreased TBM with exercise. The increased Ca++ uptake of the Sol indicates that E enhances this function, and the increased MPY probably implies an increased SR. The D could be responsible for the D-elevated Sol MPY as well as the TA PFK. El D did not reduce neuromuscular activity to a level adversely affecting oxidative enzyme activity, but in the case of PFK activity in the TA muscle, such a reduction was evident.