SHORT COMMUNICATION
The Influence of
Interleukin-1β on γ-Glutamyl Transpeptidase Activity in Rat
Hippocampus
M. KAISER1,4, V. MAREŠ2,3,
F. ŠŤASTNÝ1,2, V. BUBENÍKOVÁ-VALEŠOVÁ1, V.
LISÁ2, P. SUCHOMEL4, V.J. BALCARP5
1Laboratory of Biochemistry and Brain
Pathophysiology, Prague Psychiatric Center affiliated with
Charles University - Third Faculty of Medicine, 2Institute
of Physiology, Academy of Sciences, Prague, 3Faculty
of Science, University of J. E. Purkinje, Ústí nad Labem, 4Department
of Neurosurgery, NeuroCenter, Liberec, Czech Republic and 5Bosh
Institute for Biomedical Research and School of Medical
Sciences, The University of Sydney, New South Wales, Australia
Received May 17, 2005
Accepted September 8, 2005
On-line available October 17, 2006
Summary
Brain infections as well as peripheral challenges to the immune
system lead to an increased production of interleukin-1beta
(IL-1b), a cytokine
involved in leukocyte-mediated breakdown of the blood-brain
barrier. The effects of IL-1b
have been reported to depend on whether the route of
administration is systemic or intracerebral. Using 50-day-old
male rats, we compared the effects of IL-1b
on brain γ-glutamyl transpeptidase (GGT; an enzymatic marker of
brain capillary endothelium) at 2, 24 and 96 h after either an
intravenous (i.v.) injection of 5 μg IL-1β or an
intracerebroventricular (i.c.v. - lateral ventricle) infusion of
50 ng IL-1β. When the i.v. route was used, the GGT activity
underwent small but significant changes; decreasing in the
hippocampus 2 h after the i.v. injection, increasing 24 h later
and returning to control levels at 96 h. No significant changes
in the hippocampal GGT activity were observed at 2 and 24 h
following the i.c.v. infusion. The GGT activity in the
hypothalamus remained unchanged regardless of the route of IL-1b
administrations. Similar changes in GGT activity were revealed
histochemically. The labeling was found mainly in the capillary
bed, the changes being most evident in the hippocampal stratum
radiatum and stratum lacunosum-moleculare. A transient increase
in GGT activity at 24 h, together with a less sharp delineation
of GGT-stained vessels, may reflect IL-1b
induced increased turnover of glutathione and/or oxidative
stress, that may in turn, be related to altered permeability of
the blood-brain barrier in some neurological and mental
disorders, including schizophrenia.
Key words
Pro-inflammatory cytokine • Rat hippocampus • γ-glutamyl
transferase • Blood-brain barrier • Reactive oxygen species •
Schizophrenia
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