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- Agardh, Carl-David, et al.
(författare)
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Cerebral metabolic changes in profound, insulin-induced hypoglycemia, and in the recovery period following glucose administration
- 1978
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 31:5, s. 1135-1142
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Tidskriftsartikel (refereegranskat)abstract
- Severe hypoglycemia was induced by insulin in lightly anaesthetized (70°o N2O) and artificially ventilated rats. Brain tissue was frozen in situ after spontaneous EEG potentials had disappeared for 5. 10. 15 or 30 min and cerebral cortex concentrations of labile organic phosphates, glycolytic metabolites, ammonia and amino acids were determined. In other experiments, recovery was induced by glucose injection at the end of the period of EEG silence. All animals with an isoelectric EEG showed extensive deterioration of the cerebral energy state. and gross perturbation of amino acid concentrations. The latter included a 4-fold rise in aspartate concentration and reductions in glutamate and glutamine concentrations to 20 and 5oo of control levels respectively. There was an associated rise in ammonia concentration to about 3μmol-g-1. Administration of glucose brought about extensive recovery of cerebral energy metabolism. For example, after an isoelectric period of 30 min tissue concentrations of phosphocreatine returned to or above normal, the accumulation of ADP and AMP was reversed, there was extensive resynthesis of glycogen and glutamine and full normalisation of tissue concentrations of pyruvate. α-ketoglutarate. GABA and ammonia. However, even after 3 h of recovery there was a reduction in the ATP concentration and thereby in adenine nucleotide pool, moderate elevations of lactate content and the lactate pyruvate ratio, and less than complete restoration of the amino acid pool. It is concluded that some cells may have been irreversibly damaged by the hypoglycemia.
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| 2. |
- Bjursten, Lars Magnus, et al.
(författare)
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Behavioural repertory of cats without cerebral cortex from infancy
- 1976
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Ingår i: Experimental Brain Research. - 0014-4819. ; 25:2, s. 115-130
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Tidskriftsartikel (refereegranskat)abstract
- Bilateral removal of the cerebral cortex was made in cats neonatally. Spontaneous and imposed behaviour was studied while they were growing up and after they had become adult. Special emphasis was put on the utilization of visual cues and on learning. The cats ate, drank and groomed themselves adequately. Adequate maternal and female sexual behaviour was observed. They utilized the visual and haptic senses with respect to external space. Two cats were trained to perform visual discrimination if a T-maze. The adequacy of the behaviour of these cats is compared to that of animals with similar lesions made at maturity.
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| 6. |
- Jonsson, Gösta, et al.
(författare)
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6-Hydroxydopamine induced degeneration of noradrenaline neurons in the scorbutic guinea-pig
- 1974
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Ingår i: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952. ; 23:18, s. 2585-2593
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the neurotoxic compound 6-hydroxydopamine and its immediate precursor 6-hydroxy-DOPA on noradrenaline uptake and storage in central and peripheral catecholamine neurons of scorbutic and normal guinea-pigs has been investigated. Endogenous noradrenaline in heart and brain as well as the in vitro uptake-accumulation of 3H-noradrenaline in iris and slices of heart and brain were not significantly changed in scorbutic animals. The in vitro formation of 3H-noradrenaline from 3H-dopamine was markedly reduced in heart slices of scorbutic guinea-pigs, due to ascorbic acid being a co-factor for dopamine-β-hydroxylase. There was an increased depletion of brain noradrenaline following tyrosine hydroxylase inhibition produced by α-methyl-p-tyrosine methylester in scorbutic animals, indicating an increased NA turnover. Administration of 6-hydroxydopamine or 6-hydroxy-DOPA resulted in a similar reduction of endogenous NA in brain and heart as well as of the in vitro uptake of 3H-noradrenaline in iris, and slices from heart, cerebral cortex and hypothalamus in scorbutic and control guinea-pigs. These results are discussed in view of current hypotheses on mechanisms involved in the neurotoxic action of 6-hydroxydopamine on catecholamine neurons.
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