Effects of Hypoglycemia and Anoxia on the Central Nervous System

Gellhorn, E.

doi:10.1001/archneurpsyc.1938.02270070135010

Cited by 72 publications

(12 citation statements)

References 44 publications

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“…Whether this phenomenon is mostly attributable to a discharge of the adrenergic and cholinergic nervous system (31,49,61), or to a release of adrenal cortical hormones (previously shown to have an effect on conditioned reflexes) is open to question. In insulin shock, the hypoglycemia in itself appears to play an important role in conditioning mental processes (26,59,92,116). Interestingly, under conditions of emotional excitement, the insulin concentration of the blood (assayed in the hypophysectomized adrenodemedullated rat), is more markedly increased in psychotic than in normal individuals, although there is no corresponding hypoglycemia (28,30).…”

Section: Mayjune 19s0mentioning

confidence: 99%

Adaptive Reaction to Stress

Selye

Fortier

1950

Psychosomatic Medicine

119

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Section: Mayjune 19s0mentioning

confidence: 99%

Adaptive Reaction to Stress

Selye

Fortier

1950

Psychosomatic Medicine

119

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“…The delay in the establishment of the diagnosis in this patient, despite the presence of hypothermia, led us to raise two qeustions: (1) Are many physicians unaware of this sign? The delay in the establishment of the diagnosis in this patient, despite the presence of hypothermia, led us to raise two qeustions: (1) Are many physicians unaware of this sign?…”

mentioning

confidence: 95%

Hypothermia in Hypoglycemia

Strauch¹

1969

JAMA

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“…Other experimenters have used changes in blood pressure as criteria for analyzing the relation between hypoglycemia and anoxia in their action on the nervous system (Gellhorn, 1938). While this procedure is saris-…”

Section: Introductionmentioning

confidence: 99%

The Effects of Variations in the Concentration of Oxygen and of Glucose on Dark Adaptation

McFarland

Forbes

1940

Journal of General Physiology

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In this study we have analyzed the effects of variations in the concentrations of oxygen and of blood sugar on light sensitivity; i.e. dark adaptation. The experiments were carried out in an air-conditioned light-proof chamber where the concentrations of oxygen could be changed by dilution with nitrogen or by inhaling oxygen from a cylinder. The blood sugar was lowered by the injection of insulin and raised by the ingestion of glucose. The dark adaptation curves were plotted from data secured with an apparatus built according to specifications outlined by Hecht and Shlaer. During each experiment, observations were first made in normal air with the subject under basal conditions followed by one, and in most instances two, periods under the desired experimental conditions involving either anoxia or hyper- or hypoglycemia or variations in both the oxygen tension and blood sugar at the same time. 1. Dark adaptation curves were plotted (threshold against time) in normal air and compared with those obtained while inhaling lowered concentrations of oxygen. A decrease in sensitivity was observed with lowered oxygen tensions. Both the rod and cone portions of the curves were influenced in a similar way. These effects were counteracted by inhaling oxygen, the final rod thresholds returning to about the level of the normal base line in air or even below it within 2 to 3 minutes. The impairment was greatest for those with a poorer tolerance for low O2. Both the inter- and intra-individual variability in thresholds increased significantly at the highest altitude. 2. In a second series of tests control curves were obtained in normal air. Then while each subject remained dark adapted, the concentrations of oxygen were gradually decreased. The regeneration of visual purple was apparently complete during the 40 minutes of dark adaptation, yet in each case the thresholds continued to rise in direct proportion to the degree of anoxia. The inhalation of oxygen from a cylinder quickly counteracted the effects for the thresholds returned to the original control level within 2 to 3 minutes. 3. In experiments where the blood sugar was raised by the ingestion of glucose in normal air, no significant changes in the thresholds were observed except when the blood sugar was rapidly falling toward the end of the glucose tolerance tests. However, when glucose was ingested at the end of an experiment in low oxygen, while the subject remained dark adapted, the effects of the anoxia were largely counteracted within 6 to 8 minutes. 4. The influence of low blood sugar on light sensitivity was then studied by injecting insulin. The thresholds were raised as soon as the effects of the insulin produced a fall in the blood sugar. When the subjects inhaled oxygen the thresholds were lowered. Then when the oxygen was withdrawn so that the subject was breathing normal air, the thresholds rose again within 1 to 2 minutes. Finally, if the blood sugar was raised by ingesting glucose, the average threshold fell to the original control level or even below it. 5. The combined effects of low oxygen and low blood sugar on light sensitivity were studied in one subject (W. F.). These effects appeared to be greater than when a similar degree of anoxia or hypoglycemia was brought about separately. 6. In a series of experiments on ten subjects the dark adaptation curves were obtained both in the basal state and after a normal breakfast. In nine of the ten subjects, the food increased the sensitivity of the subjects to light. 7. The experiments reported above lend support to the hypothesis that both anoxia and hypoglycemia produce their effects on light sensitivity in essentially the same way; namely, by slowing the oxidative processes. Consequently the effects of anoxia may be ameliorated by giving glucose and the effects of hypoglycemia by inhaling oxygen. In our opinion, the changes may be attributed directly to the effects on the nervous tissue of the visual mechanism and the brain rather than on the photochemical processes of the retina.

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Effects of Hypoglycemia and Anoxia on the Central Nervous System

Cited by 72 publications

References 44 publications

Adaptive Reaction to Stress

Adaptive Reaction to Stress

Hypothermia in Hypoglycemia

The Effects of Variations in the Concentration of Oxygen and of Glucose on Dark Adaptation

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