Immunohistochemistry of tyrosine and dopamine-β-hydroxylases after experimental brain injury in the rat

A role for central norepinephrine is implicated in functional recovery after experimental brain injury. In this study, immunohistochemistry was used to examine tyrosine hydroxylase and dopamine-β-hydroxylase, enzymes involved in norepinephrine biosynthesis, in the locus coeruleus after lateral fluid percussion brain injury in rats. No discernible qualitative differences were found between the control and experimental animals in the intensities of immunostaining of either tyrosine or dopamine-β-hydroxylase in the ipsilateral left locus coeruleus at 24 h or 7 days after injury. These results suggest that the biosynthesis of norepinephrine from tyrosine hydroxylase in the locus coeruleus may not be affected by fluid percussion brain injury of moderate severity.