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Biomedical subjects

H HYDEN

Publications and source records attributed to H HYDEN.

At least 19 recordsLinked to original sources
PubMed1965

RHYTHMIC ENZYME CHANGES IN NEURONS AND GLIA DURING SLEEP.

Rhythmic changes occur in the activities of enzymes in both the neurons and neuroglia isolated from the caudal part of the reticular formation of rabbits killed during sleep and wakefulness. During sleep, enzyme activity is high in the neurons and low in the glia; during wakefulness, this situation is reversed. In the oral part of the reticular formation rhythmic enzyme changes occur only in the neurons. No rhythmic changes occur in the hypoglossal and trigeminal mesencephalic neurons and glia. These findings indicate that the caudal part of the reticular formation reflects in metabolic changes the biological clock behind the sleep rhythm.

Animals↗
PubMed1963

Inverse enzymatic changes in neurons and glia during increased function and hypoxia.

Following stimulation of the vestibular nerve in the rabbit, respiratory enzyme activities increased in Deiters' nerve cells. The anaerobic glycolysis, measured as 10(-4) microl CO(2) per hour per cell, was found to decrease concomitantly by 25 to 40 per cent, suggesting a Pasteur effect. By contrast, in the surrounding glia the anaerobic glycolysis increased and the respiratory enzyme activity decreased, suggesting a Crabtree effect. The evidence is discussed for a regulatory metabolic mechanism operating between the neuron and its glia. Hypoxia of 8 per cent O(2) caused an increase of both oxygen consumption and CO(2) production in the nerve cells, but did not change the glia values.

Animals↗
PubMed1962

A kinetic study of the neuronglia relationship.

Kinetic studies have been performed on the activity of the succinate oxidizing enzyme complex in living nerve cells and glial cells after increasing duration of stimulation. The nerve cells and glia of the lateral vestibular nucleus were used. The results show a clear difference between the neuron and its surrounding glia. The nerve cell reacted by highly increasing the capacity of the electron transporting system, reflecting an increased consumption of energy as a function of the stimulation. The glia, in contrast, did not change in this respect.

Kinetics↗
PubMed1962

Changes in the base composition of nuclear ribonucleic acid of neurons during a short period of enhanced protein production.

Nuclei from isolated nerve cells were sampled by microdissection. The content and composition of the nuclear RNA was studied and compared with that of the cytoplasmic RNA of Deiters' nerve cells of rabbits. Analyses were made of control nerve cells and of cells in which an enhanced RNA and protein production had been induced by chemical means, tricyano-amino-propene, for 60 minutes. The nuclear RNA content of the control nerve cells was 56 micromicrog, i.e. 3 per cent of the total RNA content of the nerve cell. The base ratios were: adenine 21.3, guanine 26.6, cytosine 30.8, uracil 21.3. Purine-pyrimidine analyses showed that the nuclear RNA differed significantly from the cytoplasmic RNA in having higher adenine and uracil values. The guanine and cytosine values were high, however, and the ratio G/C was 0.86 as compared with 1.16 for the cytoplasmic RNA. The composition of the nuclear RNA was interpreted as reflecting the extraordinarily strong development of the nucleolus in these neurons. During the 60 minutes of enhanced neuronal RNA production (+25 per cent) the guanine value increased and the uracil value decreased significantly in the nuclear RNA. In the cytoplasmic RNA the guanine value also increased although not so much as the nuclear guanine. The cytoplasmic cytosine value decreased. The result indicated that the production of the characteristic cytoplasmic RNA had been influenced by the change in the nuclear RNA

Adenine↗
PubMed1961

Experimentally induced changes in the base composition of the ribonucleic acids of isolated nerve cells and their oligodendroglial cells.

The effect of tricyano-amino-propene, a dimer of malononitrile, on the base composition of the RNA in isolated Deiters' nerve cells and their oligodendroglial cells has been studied using a microelectrophoretic method. Tri-a-p in a dose of 20 mg/kg has the effect of increasing the RNA and protein content per nerve cell by 25 per cent and decreasing the glia RNA by 45 per cent. The RNA base composition of the nerve cells from the control animals differs from that of their glial cells. The guanine of the nerve cell is significantly higher than that of the glia, but the content of cytosine is higher in the glia than in the RNA of nerve cell. The cytosine of nerve cells decreased significantly after tri-a-p administration. In the glial cells the cytosine showed a 20 per cent increase, and the guanine a 25 per cent decrease. Tri-a-p sharpened the difference in RNA composition already existing between the control nerve cells and their glial cells by almost 300 per cent for the guanine and by 400 per cent for the cytosine. The chemical and functional relationship between the nerve cell and its oligodendroglial cells is discussed.

Animals↗