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Transient oligemia is associated with long-term changes in binding densities of cortical inhibitory GABAA receptors in the rat brain.
- Source :
-
Brain research [Brain Res] 2009 May 19; Vol. 1271, pp. 95-102. Date of Electronic Publication: 2009 Mar 25. - Publication Year :
- 2009
-
Abstract
- Recently, we could demonstrate in rats that a short transient oligemic period of only 20-minute duration, induced by systemic hypotension, resulted in a transient decline of spatial memory capacities without any histological damage over a subsequent period of 6 months. In our present study, we checked for more subtle alterations within the highly vulnerable hippocampal CA1 subfield using quantification of neuronal cell density and semi-quantitative analysis of the ischemia-sensitive protein MAP2. Since hippocampal excitatory and inhibitory neurotransmitter receptors are crucially involved in spatial memory processes, quantitative in vitro receptor autoradiography was performed using [(3)H]MK-801, [(3)H]AMPA, and [(3)H]muscimol for labeling of NMDA, AMPA, and GABA(A) receptors, respectively. Ligand binding values were analyzed in the ischemia-sensitive hippocampal formation and in the parietal cortex. Transient oligemia did not cause any reduction of the neuronal cell density in the vulnerable CA1 subfield nor did it cause any significant changes of MAP2 protein expression in the dendritic layers of CA1. After oligemia, hippocampal binding densities of NMDA, AMPA, and GABA(A) receptors remained unchanged in all subfields investigated. Similarly, there was no difference in cortical ligand binding values of the excitatory NMDA and AMPA receptors comparing oligemic to sham-operated control rats. In the parietal cortex, however, transient oligemia caused a significant reduction of [(3)H]muscimol binding values compared to controls. These findings demonstrate long-term changes in receptor binding densities even after short oligemic periods possibly reflecting part of the molecular basis leading to impaired cognitive abilities.
- Subjects :
- Animals
Binding, Competitive physiology
Cerebral Cortex pathology
Cerebral Cortex physiopathology
Disease Models, Animal
Down-Regulation physiology
GABA Agonists metabolism
Hippocampus pathology
Hippocampus physiopathology
Hypoxia-Ischemia, Brain pathology
Hypoxia-Ischemia, Brain physiopathology
Male
Memory Disorders pathology
Memory Disorders physiopathology
Microtubule-Associated Proteins metabolism
Muscimol metabolism
Parietal Lobe metabolism
Parietal Lobe pathology
Parietal Lobe physiopathology
Radioligand Assay
Rats
Rats, Wistar
Receptors, AMPA metabolism
Receptors, N-Methyl-D-Aspartate metabolism
Time
Time Factors
Tritium metabolism
gamma-Aminobutyric Acid metabolism
Cerebral Cortex metabolism
Hippocampus metabolism
Hypoxia-Ischemia, Brain metabolism
Memory Disorders metabolism
Receptors, GABA-A metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1872-6240
- Volume :
- 1271
- Database :
- MEDLINE
- Journal :
- Brain research
- Publication Type :
- Academic Journal
- Accession number :
- 19328192
- Full Text :
- https://doi.org/10.1016/j.brainres.2009.03.028