Nitric oxide release and contractile properties of skeletal muscles from mice deficient in type III NOS.

Skeletal muscle constitutively expresses both the type I (neuronal) and type III (endothelial) isoforms of nitric oxide synthase (NOS). We tested the functional importance of type III NOS using skeletal muscles with similar levels of type III NOS expression (diaphragm and soleus) from wild-type, heterozygous, and type III NOS-deficient littermate mice. Muscles were incubated at 37 degrees C in Krebs-Ringer solution.

Diaphragmatic lipid peroxidation in chronically loaded rats.

Recent work indicates that free radical-mediated lipid peroxidation takes place within the diaphragm on strenuous contraction. This phenomenon has only been demonstrated using fairly artificial experimental models and has not been studied during the type of sustained respiratory loading typically seen in patients with lung disease. The purpose of the present study was to measure the levels of several biochemical markers of protein oxidation (protein carbonyl levels) and lipid peroxidation (8-isoprostane, reduced glutathione, and oxidized glutathione levels) in diaphragms of rats subjected to chronic respiratory loading.