Immunohistological determination of ecto-nucleoside triphosphate diphosphohydrolase1 (NTPDase1) and 5'-nucleotidase in rat hippocampus reveals overlapping distribution

Distribution of two enzymes involved in the ectonucleotidase enzyme chain, ecto-nucleoside triphosphate diphosphohydrolase1 (NTPDase1) and ecto-5'-nucleotidase, was assessed by immunohistochemistry in the rat hippocampus. Obtained results have shown co-expression of the enzymes in the hippocampal region, as well as wide and strikingly similar cellular distribution. Both enzymes were expressed at the surface of pyramidal neurons in the CA1 and CA2 sections, while cells in the CA3 section were faintly stained. The granule cell layer of the dentate gyrus was moderately stained for NTPDase1, as well as for ecto-5'-nucleotidase. Glial association for ecto-5'-nucleotidase was also observed, and fiber tracts were intensively stained for both enzymes. This is the first comparative study of NTPDase1 and ecto-5'-nucleotidase distribution in the rat hippocampus. Obtained results suggest that the broad overlapping distribution of these enzymes in neurons and glial cells reflects the functional importance of ectonucleotidase actions in the nervous system.