Nov 6, 2004

The peroxynitrite pathway in development: phenytoin and benzo[a]pyrene embryopathies in inducible nitric oxide synthase knockout mice

Free Radical Biology & Medicine
Sonja KasapinovicPeter G Wells


Nitric oxide generated by nitric oxide synthases (NOSs) can react with reactive oxygen species (ROS), forming peroxynitrite, which may contribute to the ROS-initiated macromolecular damage implicated in the embryopathic effects of both endogenous and drug-enhanced oxidative stress. Inducible NOS (iNOS) is nonconstitutive in most tissues, and its embryonic expression and developmental importance are unknown. Herein, during organogenesis (Gestational Days 9 and 10), wild-type B6129PF2 embryos in culture were highly susceptible to the ROS-initiating teratogens phenytoin and benzo[a]pyrene, whereas iNOS knockout embryos were substantially but not completely protected (p < .05), implicating iNOS in the embryopathic mechanism. However, in contrast to prostaglandin H synthase-catalyzed teratogen bioactivation and ROS formation, which occurs within the embryo, in vivo iNOS expression was limited to placental tissue. These results suggest that the diffusion of nitric oxide from placental progenitor tissue (ectoplacental cone) to embryonic target tissues contributes to the embryopathic effects of ROS-initiating teratogens in embryo culture, which may constitute a mechanism by which embryonic determinants of ROS-mediated teratogenesis can...Continue Reading

  • References31
  • Citations15


  • References31
  • Citations15

Mentioned in this Paper

Pathologic Cytolysis
Establishment and Maintenance of Localization
ISYNA1 gene
Biochemical Pathway
Polyvinylidene fluoride
Dimethyl Sulfoxide
NOS1 protein, human

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