Influence of ribose on adenine salvage after intense muscle contractions

The influence of ribose supplementation on skeletal muscle adenine salvage rates during recovery from intense contractions and subsequent muscle perfo rmance was evaluated using an adult rat perfused hindquarter preparation. T hree minutes of tetanic contractions (60 tetani/min) decreased ATP content in the calf muscles by similar to 50% and produced an equimolar increase in IMP. Effective recovery of muscle ATP 1 h after contractions was due to re amination of IMP via the purine nucleotide cycle and was complete in the re d gastrocnemius but incomplete in the white gastrocnemius muscle section. A denine salvage rates in recovering muscle averaged 45 +/- 4, 49 +/- 5, and 30 +/- 3 nmol.h(-1).g(-1) for plantaris, red gastrocnemius, and white gastr ocnemius muscle, respectively, which were not different from values in corr esponding nonstimulated muscle sections. Adenine salvage rates increased fi ve- to sevenfold by perfusion with similar to4 mM ribose (212 +/- 17, 192 /- 9, and 215 +/- 14 nmol.h(-1).g(-1) in resting muscle sections, respectiv ely). These high rates were sustained in recovering muscle, except for a sm all (similar to 20%) but significant (P < 0.001) decrease in the white gast rocnemius muscle. Ribose supplementation did not affect subsequent muscle f orce production after 60 min of recovery. These data indicate that adenine salvage rates were essentially unaltered during recovery from intense contr actions.