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

Abstract

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.

Fig. 1

Immunoblot analysis for the specificity of the antibodies against NTPDase1 (A) and 5′-ectonucleotidase (B). Lane 1 on each blot shows molecular weight markers

Fig. 2

Immunolocalization of NTPDase1 in the rat hippocampus. (A) Low-power photomicrograph of hippocampal area immunostained with the anti-NTPDase1 antibody. (B) High-power photomicrograph magnified from the area enclosed by a rectangle B in A, showing SP of CA1 region with marked apical dendrites (arrowheads). Arrows point to immunopositive neurons in SO. (C) Photomicrograph magnified from the area C enclosed in A, showing IR of pyramidal neurons in CA2 area; arrows point to interneurons in SO. (D) The granule cell layer of DG and PoDG, with putative glial distribution (arrows). (E) High-power photomicrograph of DG showing granule cells with marked apical dendrites (arrows). (F) Photomicrograph magnified from the area enclosed in A showing faint IR in CA3 region. (G) Omission of the primary antibody resulted in no specific staining. Scale bar: 500 μm in A; 50 μm in B–D; 25 μm in E and F

Fig. 3

Immunolocalization of ecto-5′-nucleotidase in the rat hippocampus. (A) Low-power photomicrograph of hippocampal area immunostained with the anti-5′-nucleotidase antibody. (B) Photomicrograph magnified from the area enclosed by a rectangle B in A, showing the IR in the CA1 area. Arrows point to the immunoreactive interneurons in SO. (C) High-power micrograph magnified from B, showing pyramidal cells with marked apical dendrites (arrows) and large neuron in SR (arrowhead). (D) Capillaries and larger blood vessels in SLM showed positive on ecto-5′-nucleotidase (arrows). Astrocytes were also detected (arrowheads). (E) Pyramidal neurons in CA2 region with pronounced apical dendrites (arrowheads). (F) Pyramidal cells in CA3 region, enlarged photomicrograph from A. (G) The pyramidal cells and strongly positive astrocytes interposed in hilus (arrows). (H) The granular cell layer of DG. (I) High-power photomicrograph enlarged from H, showing the pattern of staining of granule cells, with pronounced apical dendrites (arrows). (J) High-power photomicrograph enlarged from A showing astrocytes with pronounced processes in PoDG. (K) Omission of the primary antibody resulted in no specific immunostaining. Scale bar: 500 μm in A; 100 μm in B and D; 50 μm in E–H; 25 μm in C and J