Identification of dopaminergic nerves in humans.

It has been well-documented in animal studies that axons of dopaminergic neurons can be distinguished from those of noradrenergic neurons by their content of DOPA decarboxylase (DDC). We now have evidence that DDC immunoreactivity is also specific for dopaminergic axons in the sympathetic nervous system of man. Thus, light microscope immunocytochemistry can be used to screen human tissues for potential dopaminergic inputs, preparatory to functional analysis. Application of this technique has so confirmed the innervation by dopaminergic neurons of human kidney and hepatic vasculature. Although similar nerves are found in kidney and liver of dog, the specific target structures supplied, and therefore the specific functional effects of nerve activation, are different.