Immunohistochemical localization of ADP-ribosylarginine hydrolase in rodent CNS.

Polyclonal antibodies were generated against ADP-ribosylarginine hydrolase (AAH), using recombinant fusion protein of rat AAH and glutathione-S-transferase as a immunogen, and affinity-purified. Western blotting showed that the antibodies recognized in mouse brain homogenate a single protein with a molecular mass of 38 kDa, the expected size for mouse AAH. An analysis using the antibodies revealed that heavy labelings were apparent in various brain regions. In the cerebral cortex, pyramidal cells in layers III and V were the most heavily labeled. In the hippocampal formation, labeling was present on the pyramidal neurons and granule cells. The most heavily immunostained cell type was the pyramidal neuron of CA3. In the cerebellum, Purkinje cells were the most heavily labeled. Less intense staining was present over the granule cells. In the basal ganglia, neurons in the caudate nucleus and large multipolar cells in the amygdaloid complex were immunoreactive. Heavy labeling was seen in many midbrain and brainstem nuclei. Neurons in the habenula and ependymal cells were stained heavily. On Western blot analysis of rat cerebrospinal fluid (CSF), the anti-AAH antibodies recognized a protein with a molecular mass of 38 kDa. This is apparently the first evidence of a widespread but distinctive distribution of AAH in neurons of mouse brain and the presence of extracellular AAH in rat CSF.