Quantitative imaging of tyrosine hydroxylase and calmodulin in the human brain

The distributions of tyrosine hydroxylase and calmodulin in adult normal po stmortem human brain were analyzed quantitatively. Consecutive coronal sect ions were obtained from the anterior area of the right hemisphere and were stained immunohistochemically for tyrosine hydroxylase and calmodulin. Stai ned sections were divided into approximately 3 million microareas at 50 mum intervals, and the immunohistochemical fluorescence intensity in each area was measured by a human brain mapping analyzer, which is a microphotometry system for analysis of the distribution of neurochemicals in a large tissu e slice. Immunoreactive staining of tyrosine hydroxylase and calmodulin was observed in almost all brain regions, but its intensity varied. Relatively high levels of calmodulin were observed in brain regions with high levels of tyrosine hydroxylase, though high levels of tyrosine hydroxylase were no t always observed in brain regions where high levels of calmodulin were dis tributed. In particular, high levels of both of tyrosine hydroxylase and ca lmodulin were distributed in the caudate nucleus and putamen. Previously it was shown that tyrosine hydroxylase was activated and dopamine synthesis w as enhanced in the neostriatum region in mice and rats by the intracerebrov entricular administration of calcium through a calmodulin-dependent system. The present results combined with these previous findings suggest that the activity of tyrosine hydroxylase in the caudate nucleus and putamen of hum ans may also be regulated by a calcium/calmodulin-dependent system. (C) 200 1 Wiley-Liss, Inc.