Physiol. Res. 55: 461-465, 2006


The Influence of Interleukin-1β on γ-Glutamyl Transpeptidase Activity in Rat Hippocampus


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

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

© 2006 by the Institute of Physiology, Czech Academy of Sciences