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Changes in ligand binding to adrenoceptors ([3H]prazosin to α1-receptors, [3H]idazoxan to α2-receptors and [125I]cyanopindolol to β-receptors) following transient cerebral ischemia were investigated using autoradiographic methods. The binding was quantified in brain sections from control rats, rats subjected to 15 min of 2-vessel occlusion ischemia, and rats with recirculation times of 1 h, 1 week
Abstract: The changes in the levels of protein kinase C [PKC(α, βII, γ)] were studied in cytosolic and particulate fractions of striatal homogenates from rats subjected to 15 min of cerebral ischemia induced by bilateral occlusion of the common carotid arteries and following 1 h, 6 h, and 48 h of reperfusion. During ischemia the levels of PKC(βII) and ‐(γ) increased in the particulate fraction to
: The effect of hypothermia on the ischemia‐induced changes in the subcellular distribution of protein kinase C (PKC)(γ), ‐(βII), and ‐(α) and the activity of PKC was studied in striatal homogenates of rats subjected to 20 min of cerebral ischemia. The effect of post‐ischemic cooling was also studied. During normothermic ischemia, PKC(γ) and ‐(βII) increased 3.9‐and 2.9‐fold, respectively, in the
Glutamate is an important factor in the mechanisms of neuronal damage following cerebral ischemia. Blockade of one type of glutamate receptor, the N-methyl-D-aspartate (NMDA) receptor, decreases brain infarct size in experimental models of permanent focal ischemia, but protection in models of transient reversible ischemia is ambiguous. We investigated the effect of the noncompetitive NMDA receptor
The effect of severe insulin-induced hypoglycemia on the activity of the pyruvate dehydrogenase enzyme complex (PDHC) was investigated in homogenates of frozen rat cerebral cortex during burst suppression EEG, after 10, 30, and 60 min of isoelectric EEG, and after 30 and 180 min and 24 h of recovery following 30 min of hypoglycemic coma. Changes in PDHC activity were correlated to levels of labile
A high-resolution 270-MHz proton NMR study of procine colipase I has been performed, and the resonances in the aromatic region of the spectrum have been assigned to amino acid residues by pH titration and decoupling experiments. The apparent pKa values of the three tyrosines were calculated to be 10.2, 10.3, and 11.8 with one of the tyrosines having properties of a “buried” residue. A tentative as
The translational mobility of aggregates formed in aqueous sodium cholate solutions was obtained from the self-diffusion coefficient of solubilized decanol, which was determined using the capillary tube method with radioactive labeling. Combining these results with the self-diffusion coefficients of cholate ions, sodium ions, and water molecules the following quantities were determined as a functi
Using microdialysis, extracellular noradrenaline (NA) levels in the rat cerebral cortex were studied under isoflurane/N2O anaesthesia before, during and for 6 hours following 10 min of forebrain ischemia in a 2-vessel occlusion model. A microdialysis probe was introduced into the parietal cortex and dorsal hippocampus in anaesthetized rats and continuously perfused with Krebs-Ringerbicarbonate buf
Transient periods of global cerebral ischemia lead to selective neuronal damage in the striatum. We investigated the effects of unilateral 6-hydroxydopamine lesions of the mesostriatal dopamine (DA) system on the density and distribution of neuronal necrosis in the rat striatum following ischemia induced by bilateral occlusion of the common carotid arteries combined with hypotension. After both 12
Transient cerebral ischemia in normoglycemic animals is followed by a decrease in glucose utilization, reflecting a postischemic cerebral metabolic depression and a reduction in the activity of the pyruvate dehydrogenase complex (PDHC). Preischemic hyperglycemia, which aggravates ischemic brain damage and invariably causes seizure, is known to further reduce cerebral metabolic rate. To investigate
Extracellular concentrations of the brain metabolite quinolinic acid, an endogenous excitotoxin, were monitored by microdialysis in rat neostriatum and hippocampus/cortex during and following a 30-min period of insulin-induced hypoglycaemia. During hypoglycaemia-induced isoelectricity, extracellular levels of quinolinic acid in the striatum (basal value, 1.1 ± 0.3 pmol per 30-μl fraction) were ele
Disruption of intracellular calcium homeostasis is thought to play a role in neurodegenerative disorders such as Huntington's disease (HD). To study different aspects of putative pathogenic mechanisms in HD, we aimed to establish an in vitro model of calcium-induced toxicity in striatal neurons. The calcium ionophore A23187 induced a concentration- and time-dependent cell death in cultures of embr
The mitochondrial permeability transition pore is an inducer of cell death. During the reperfusion phase after cerebral ischemia, calcium accumulates in mitochondria, and a burst of free radical formation occurs, conditions that favor the activation of the mitochondrial permeability transition pore. Here the authors demonstrate that a blocker of the mitochondrial permeability transition pore, the
A brief period of sublethal cerebral ischemia, followed by several days of recovery, renders the brain resistant to a subsequent lethal ischemic insult, a phenomenon termed ischemic preconditioning or tolerance. Ischemic tolerance was established in the rat two-vessel occlusion model of ischemia, induced by occlusion of both carotid arteries in combination with hypotension. Ischemic preconditionin
A short period of sublethal preconditioning ischemia (3 min) followed by two days of reperfusion provides almost complete protection against ischemic cell death induced by a second (9 min) lethal ischemic episode. Here, we have investigated the extracellular signal-regulated protein kinase kinase and extracellular signal-regulated protein kinase, two kinases known to activate gene transcription an
Mitochondria from different regions of the brain were prepared, and the activation of the mitochondrial permeability transition (MPT) by calcium was investigated by monitoring the associated mitochondrial swelling. In general, the properties of the MPT in brain mitochondria were found to be qualitatively similar to those observed in liver and heart mitochondria. Thus, swelling was inhibited by ade
