Expression of ecto-nucleoside triphosphate diphosphohydrolase3 (NTPDase3) in the female rat brain during postnatal development

Abstract

Nucleoside triphosphate diphosphohydrolase3 (NTPDase3) is membrane-bound ectoenzyme which hydrolyzes extracellular ATP, thus modulating the function of purinergicreceptors and the pattern of purinergic signaling. Here we analyzed the developmentalexpression of NTPDase3 in female hypothalamus, cerebral cortex and hippocampal formationat different postnatal ages (PD7–PD90) by qRT-PCR and immunohistochemistry. Inhypothalamus and hippocampus, a similar developmental profile was seen: NTPDase3 geneexpression was stable during postnatal development and increased in adults. In the cortex,upregulation of NTPDase3 mRNA expression was seen at PD15 and further increase wasevidenced in adults. Immunohistochemical analysis at PD7 revealed faint neuronal NTPDase3localization, in dorsal hypothalamus. The immunoreactivity (ir) gradually increased in PD15and PD20, in clusters of cells in the lateral, ventral and dorsomedial hypothalamus.Furthermore, in PD20 animals, NTPDase3-ir was detected on short fibers in the posteriorhypothalamic area, while in PD30 the fibers appeared progressively longer and markedlyvaricose. In adults, the strongest NTPDase3-ir was observed in collections of cells indorsomedial hypothalamic nucleus, dorsal and lateral hypothalamus and in several thalamicareas, whereas the varicose fibers traversed entire diencephalon, particularly paraventricularthalamic nucleus, ventromedial and dorsomedial hypothalamic nuclei, the arcuate nucleus andthe prefornical part of the lateral hypothalamus. The presumably ascending NTPDase3-irfibers were first observed in PD20; their density and the varicose appearance increased untilthe adulthood. Prominent enhancement of NTPDase3-ir in the hypothalamus coincides withage when animals acquire diurnal rhythms of sleeping and feeding, supporting the hypothesisthat this enzyme may be involved in regulation of homeostatic functions.