The Role of Reactive Oxygen Species in the Tone Regulation of Respiratory and Locomotor Muscle Arteries of the Rat

— The production of reactive oxygen species (ROS) in skeletal muscle cells increases under contraction. Respiratory and locomotor muscles differ in contraction modes; therefore, ROS production and their effect on blood vessels in these functionally different types of muscles may differ. The aim of this work was to assess the role of ROS in the tone regulation of the diaphragm artery ( a. phrenica ) and deep brachial artery ( a. profunda brachii ) of the rat. The reactions of ring preparations of the arteries were studied in the isometric regimen. The NADPH oxidase (NOX) inhibitor VAS2870 caused relaxation of the preparations; the reaction magnitude of the diaphragm arteries was greater than that of the brachial arteries: at the VAS2870 concentration of 1 μM, the contraction force decreased to 33 and 91