Nitrotyrosine immunoreactivity in gerbil hippocampal CA1 region after transient forebrain ischemia

We examined whether or not nitration of tyrosine residues takes place in the gerbil hippocampal CA1 region after transient forebrain ischemia, The nitration of tyrosine residues to produce nitrotyrosine is a footprint of peroxynitrite, a reaction product of nitric oxide (NO) with superoxide, Nitrotyrosine immunoreactivity had been detected in the CA1 region from the early stage in a reperfused brain at 30 min after transient ischemia until DIVA fragmentation and neuronal death appeared at 4 days after transient ischemia, In electron microscopy, we detected, prominently, nitrotyrosine immunoreactivity after transient ischemia in the cytoplasm of the CA1 neurons. Therefore, it is considered that the nitration of tyrosine residues by peroxynitrite may be closely related to apoptosis after transient ischemia.