Effects of carbonic anhydrase inhibitors on oxygen consumption and lactate accumulation in skeletal muscle

Abstract

In isolated rat soleus and extensor digitorum longus (EDL) muscles, the effects of carbonic anhydrase inhibitors were studied on oxygen consumption as well as lactate release and accumulation after incubation in inhibitors lasting long enough to produce marked changes in contractile parameters and in the concentrations of energy-rich phosphates. The inhibitors used were chlorzolamide (10(-3) M) and NaCNO (10(-2) M). Compared with control muscles, muscles treated with either of the two inhibitors showed a decrease in force, and an increase in time-to-peak as well as in relaxation time. Lactate content and release in soleus and in EDL were increased by factors of 2-3 with both inhibitors. With both inhibitors, oxygen consumption in the red soleus increased by approximately 27%, whereas in EDL, no significant change could be observed. The increase in aerobic metabolic rate in the red soleus only might indicate that the isozyme CA III, which is present only in this type of muscle, is in some way involved in keeping the oxygen consumption low. The increase in anaerobic metabolic rate occurring in both muscles can possibly be explained by increases in Pi and ADP.