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A model is described in which transient complete cerebral ischemia is induced in rats by intracardiac injection of potassium chloride. The animals were intubated and mechanically ventilated with a nitrous oxide/oxygen (70:30) mixture. Cardiac arrest was achieved following a brief period of ventricular fibrillation. After 5-6 min, the circulation was restored by cardiopulmonary resuscitation and pa
Ischemic brain insults are accompanied by several metabolic alterations. In the present review, the adverse reactions, which might be important for the outcome of these insults, are those related to phospholipid and polyunsaturated fatty acid metabolism triggered by the disturbed calcium ion homeostasis in combination with energy depletion following ischemia. These conditions lead to an activation
The effect of flunarizine, a calcium entry blocker, on ischaemic damage was investigated using a new model of forebrain ischaemia. Fasted rats were subjected to nine minutes ischaemia and one week recovery. One group served as control; a second was pretreated orally with flunarizine; a third group received postischaemic flunarizine treatment Focussing on the hippocampus, an area of high susceptibi
To study the influence of acidosis on free radical formation and lipid peroxidation in brain tissues, homogenates fortified with ferrous ions and, in some experiments, with ascorbic acid were equilibrated with 5–15% O2 at pH values of 7.0, 6.5, 6.0, and 5.0, with subsequent measurements of thiobarbituric acid-reactive (TBAR) material, as well as of water- and lipid-soluble antioxidants (glutathion
The effect of lesions of two excitatory afferent pathways on the cellular damage in the hippocampus following complete cerebral ischaemia was investigated in the rat Lesions transecting the perforant path led to a significant decrease in cellular damage in the hippocampal CA1 region ipsilateral to the lesion as compared to the contatterai side and to control. Lesions of the fimbria-fornix, on the
Abstract: The concentrations of cyclic AMP, noradrenaline, glycogen, glucose, lactate, pyruvate, labile phosphate compounds, and free fatty acids were investigated in the rat neocortex and hippocampus during and following cerebral ischemia. An incomplete ischemia of 5 and 15 min duration was induced by bilateral carotid clamping combined with hypotension. The postischemic events were studied afte
A detailed light- and electron-microscopic study of the damage to the rat dentate gyrus in hypoglycemia was undertaken, in view of the previously advanced hypothesis that hypoglycemic nerve cell injury is mediated by a released neurotoxin. The distribution of neuronal necrosis showed a relationship to the subarachnoid cisterns. Electron microscopy of the dentate granule cells and their apical dend
The kinetics of trypsin activation of pancreatic procolipase was investigated and the pH dependence of the binding of procolipase and colipase to a tributyrine-bile salt interface studied. The Km was 0.06 mM and Kcat 8 s-1, and was of the same order of magnitude as for the activation of pancreatic zymogens. At basic pH values colipase had a higher affinity for the tributyrine-bile salt interface a
The effects of inhaled 1,1,1-trichloroethane (3500, 6000, and 7800 ppm) on behavior, local cerebral blood flow, and local cerebral glucose consumption were studied in awake rats. The effect of the solvent inhalation on the EEG pattern and local cerebral blood flow was also studied in paralyzed animals under N2O analgesia. Exposure of awake animals to 6000 ppm 1,1,1-trichloroethane induced a decrea
Abstract: In the cerebral cortices of rats, during insulininduced hypoglycemia, changes in the concentrations of labile phosphate compounds [ATP, ADP, AMP, and phosphocreatine (PCr)] and glycolytic metabolites (lactate, pyruvate, and glucose) as well as phospholipids and free fatty acids (FFAs) were studied in relation to extracellular potassium and calcium activities. Changes in extracellular ca
ABSTRACT— A model is described in which transient ischemia is induced in rats anaesthetized with N2O:O2 (70:30) by bilateral carotid artery clamping combined with a lowering of mean arterial blood pressure to 50 mm Hg, the latter being achieved by bleeding, or by bleeding supplemented with administration of trimetaphan or phentolamine. By the use of intubation, muscle paralysis with suxamethonium
Calcium ion binding to phospholipase A2 and its zymogen has been studied by 43Ca NMR. The temperature dependence of the band shape of the calcium-43 NMR signal has been used to calculate the calcium ion exchange rate. The on-rate was calculated to be 5 × 106 M-1 s-1, which is 2 orders of magnitude less than the diffusion limit of the hydrated Ca2+ ion in water. The 43Ca quadrupole coupling constan
This study explores the possibility that the delayed hypoperfusion observed after an ischemic insult might be due to vasoconstriction induced by the release of noradrenaline from nerves originating in the locus ceruleus. Bilateral 6-hydroxydopamine lesions of the ascending bundles from the locus ceruleus were carried out in the caudal mesencephalon of rats. Local CBF was measured with an autoradio
The changes in extracellular Ca2+ (Cae) and K+ (Ke) activities were studied in the rat brain during insulin-induced hypoglycemia. At about the time of onset of isoelectric EEG in severe insulin-induced hypoglycemia (300-g male Wistar rats under 70% N2O anaesthesia), there was an increase in Ke which, at ∼13 mM, was associated with a fall in Cae. Ke peaked at 48 ± 12 mM, and Cae at 0.18 ± 0.28 mM.
Abstract: Noradrenaline (NA) metabolism tn the neocortex and hippocampus was examined in rats atl 1, 24, and 48 h following 15 min of reversible forebrain ischemia. As assessed by the ratio of accumulated 3,4‐dihydroxyphenylalanine (DOPA) to the tissue NA level after inhibition of DOPA decarboxylase, the NA turnover rates were markedly increased (120‐148% above the control) at 1 h postischemia in
Levels of excitatory amino acids in the brain extracellular fluid compartment rise during pathological conditions in the brain such as ischaemia, anoxia and epilepsy. One such amino acid, glutamate, is present in sensory nerve fibres innervating, for example, cerebral vessels. Enhanced levels of circulating glutamate and aspartate are found in migraine sufferers. The present study examined whether
