NOS3 and endothelial dysfunction: Endothelial dysfunction in inflamed dental pulp can be caused by a number of factors, including a reduction in the bioavailability of L-arginine, the uncoupling of eNOS through the oxidation of BH4 to BH2, the inactivation of endogenous NO by O2− forming ONOO−, increased cellular concentrations of the eNOS inhibitor ADMA, and ROS- and RNS-oxidized, heme-free and thus NO-insensitive NO-GC.