Effect of guanethidine-induced adrenergic blockade on the different proteolytic systems in rat skeletal muscle

Luiz Carlos C. Navegantes, Neusa M. Z. Resano, Renato H. Migliorini, Isis C. Kettelhut
1999 American Journal of Physiology. Endocrinology and Metabolism  
Navegantes, Luiz Carlos C., Neusa M. Z. Resano, Renato H. Migliorini, and Isis C. Kettelhut. Effect of guanethidine-induced adrenergic blockade on the different proteolytic systems in rat skeletal muscle. Am. J. Physiol. 277 (Endocrinol. Metab. 40): E883-E889, 1999.-Overall proteolysis and the activity of skeletal muscle proteolytic systems were investigated in rats submitted to guanethidine-induced adrenergic blockade for 4 days. In soleus, overall proteolysis increased by 15-20% during the
more » ... 5-20% during the first 2 days of guanethidine treatment but decreased to levels below control values after 4 days. Extensor digitorum longus (EDL) did not show the initial increase in total proteolysis, which was already reduced after 2 days of guanethidine treatment. The initial rise in the rate of protein degradation in soleus was accompanied by an increased activity of the Ca 2ϩ -dependent proteolytic pathway. In both soleus and EDL, the reduction in overall proteolysis was paralleled by decreased activities of the Ca 2ϩ -dependent and ATP-dependent proteolytic processes. No change was observed in the activity of the lysosomal proteolytic system. Overall proteolysis in soleus and EDL from nontreated rats was partially inhibited by isoproterenol, in vitro. The data suggest an acute inhibitory control of skeletal muscle proteolysis by the adrenergic system, well evident in the oxidative muscle, with an important participation of the Ca 2ϩ -dependent pathway. catecholamines; isoproterenol; lysosomal proteolytic activity; calcium-dependent proteolysis; ATP-dependent proteolysis
doi:10.1152/ajpendo.1999.277.5.e883 pmid:10567016 fatcat:hjjitf3lvvfhppmmvurpbmqubq