The effect of nitrogen oxide level modulation on the content of thiol compounds and anaerobic sulfur metabolism in mice brains.

Aminoguanidine (AG) an inhibitor of NO-synthase reduces cysteine (Cys), cystine (CC), sulfane sulfur (SS) and glutathione (GSH) in brain stems but practically has no effects on the levels of reactive oxygen species (ROS). In cortex AG decreases to a lower degree the concentration of Cys, CC, GSH but in this brain part significantly decreases ROS levels and increases SS. Under the AG action cystathionase (CST) activity very seriously decreases in stems and in cortex and simultaneously activity of 3-mercaptopyruvate sulfurtransferase (MPST) increases. The morpholinosydnonimine (SIN-1) the specific donor of NO and O2 only slightly reduces Cys and GSH in brain stems and ROS and SS remain at the control levels. Simultaneously, there is an increase in cortex of the amounts of GSH with the reduction of ROS and SS. Furthermore, SIN-1 seriously decreases in stems and cortex the activity of CST and increases the activity of MPST. These results confirmed the relationship between intracellular levels of NO, sulfhydryl groups, ROS, and anaerobic sulfur metabolism.