Figure 5. ATP ectonucleotidase activity localizes sharply to neurogenic regions of the brain.

(A) P2Y receptor expression extended throughout the telencephalic ventricular zone of embryonic brain (E14). P2Y expression was more sharply localized to ependymal and subependymal layer of the adult ventricular wall (P51). (B) ATP ectonucleotidase activity (left) in the adult brain was localized to the striatal ventricular wall, extending dorsolaterally to the take-off of the rostral migratory stream (inset). A no-ATP control for the specificity of the ectonucleotidase histochemistry, right). Lesser degrees of enzyme activity were also noted in the callosal wall. (C) The subgranular zone of the dentate gyrus also exhibited prominent ectonucleotidase activity. The striatal ventricular wall, RMS and dentate are the only persistently neurogenic regions of the adult brain, and were the only regions to exhibit high levels of ectonucleotidase activity. (D) Comparison of ATP ectonucleotidase activity in the dentate (subgranular zone (SGZ), the molecular layer, and the granular zone), as well as the ventricular zone, rostral stream, stratum radiatum, and corpus callosum. Enzyme activity was quantified on representative bright field images in 3 independent experiments. Insert Comparison of relative enzyme activity in non-neurogenic areas (including the molecular and granular zone of the dentate, as well as the stratum radiatum and corpus callosum) and neurogenic zone (SGZ, ventricular zone, and rostral stream). Neurogenic zones exhibited a substantial higher ATP ectonucleotidase activity than non-neurogenic zones. *; p < 0.0001, t-test.