Premium
Dynamic changes in the expression pattern of ecto‐5′‐nucleotidase in the rat model of cortical stab injury
Author(s) -
Bjelobaba Ivana,
Parabucki Ana,
Lavrnja Irena,
Stojkov Danijela,
Dacic Sanja,
Pekovic Sanja,
Rakic Ljubisa,
Stojiljkovic Mirjana,
Nedeljkovic Nadezda
Publication year - 2011
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.22599
Subject(s) - 5' nucleotidase , stab , neuroscience , biology , medicine , anatomy , adenosine
Traumatic injury induces massive release of ATP in the extracellular space, where it influences numerous aspects of neuronal, astrocytic, and microglial responses to injury by activating P2X and P2Y receptors. The extracellular ATP actions are controlled by the ectonucleotidase enzyme pathway, which hydrolyses ATP to adenosine at all neuronal and nonneuronal cell types. Adenosine activates its P1 receptors, which have important neuroprotective roles. The rate‐limiting enzyme in the ectonucleotidase pathway is ecto‐5′‐nucleotidase (e‐5NT), which catalyzes the final step of dephosphorylation of AMP to adenosine. The aim of the present study was to characterize the expression pattern and cellular distribution of e‐5NT in the perilesioned cortex at 4 hr and 1, 2, 7, and 15 days after unilateral cortical stab injury (CSI). Immunoblot and immunohistochemical studies showed that overall e‐5NT expression was lower 4 hr and 1 day postinjury and then gradually increased above the control levels. Double‐immunofluorescence studies further showed in control tissue the presence of the enzyme in the membranes surrounding neuronal somata and apical dendrites and less frequently in astrocytes. CSI caused a rapid (after 4 hr) and irreversible loss of the enzyme from neurons, accounting for a decrease in the overall enzyme expression. This was accompanied with a gradual increase in e‐5NT‐positive astrocytes, accounting for up‐regulation of the enzyme levels in the injured area. Thus, CSI induced dynamic changes in the expression pattern of e‐5NT that modify the ATP/adenosine ratio and the extent of P1 and P2 receptors activation and, therefore, outcome of the pathological processes after CSI. © 2011 Wiley‐Liss, Inc.