JAMA 100 Years Ago December 20, 1913

The Resistance of Various Nerve-Cells to Anemia The nervous system of higher animals is exceedingly sensitive to anemia or other physiologic conditions which involve a local lack of oxygen. Muscle tissue which has been supplied inadequately with this essential element or perhaps completely deprived of it for not inconsiderable periods of time may still show a satisfactory recovery of contractile power when the circulation is suitably restored and the resuscitating oxygen reaches the asphyxiated tissue-cells, but this is not the case with the nervous tissues. The nerve-cells of different classes and positions show differences in sensitiveness to anemia. Those of the cerebrum and cerebellum are unquestionably most readily damaged by oxygen starvation. There is evidence to show, for example, that eight minutes of complete anemia may permanently eliminate the function of some of the cells of the cortical areas. If the blood-supply there is wanting for more than twenty minutes it is rarely possible to discover restoration when the circulation is reestablished. In descending to the lower levels of the cerebrospinal nervous system the resistance to the detrimental effects of anemia or the immunity from permanent damage by lack of oxygen increases appreciably. In sequence the cells of the spinal bulb, the spinal cord and the spinal ganglia, respectively, appear to withstand anemia for longer and longer periods, so that a cessation of the circulation for eight or ten minutes may be of minor significance and permit of prompt complete recovery when the blood-supply is restored. Anemia of the spinal cord for an hour, however, is reported to be sufficient to cause necrosis of all the nervous elements. A growing appreciation of the foregoing facts helps to explain the unfortunate outcome of conditions, as for example those following the oxygen starvation induced by carbon monoxid or coal-gas poisoning, in which there is acute oxygen want. Certain resulting permanent paraplegias are included in this group. The permanent disastrous results of oxygen want in the nervous retina induced by obstruction of the retinal vessels belong in the same category. Whether there are other neurons in the body which have a greater hardiness than those of the cerebrospinal axis, as just cited, has not hitherto been determined, though there have been intimations that some of the outlying cells, such as those of the sympathetic ganglia, are more stable in the absence of their blood-supply.

Editor’s Note: JAMA 100 Years Ago is transcribed verbatim from articles published a century ago, unless otherwise noted. 2570

The persistence with which portions of the small intestine will exhibit rhythmic contractility long after their removal from the body, if they are treated with an oxygenated restorative like warmed Ringer’s solution, suggests that their nervous supply, or more specifically the cells of the myenteric plexus, are exceptionally resistant to anemia. The basis for this assumption of survival of the nervous elements is the generally accepted evidence that rhythmic contractions of the alimentary canal do not occur if the plexus is wanting.1 Quite apart from the purely theoretical aspect of the question, the determination of the degree of resistance of the intrinsic neurons of the alimentary tract to anemia and their limits of endurance are of interest in connection with the possibility of continued functioning after the interference with the circulation in surgical states such as hernia and intussusception. An experimental inquiry conducted in the Harvard laboratory of W. B. Cannon, to whom we are already indebted for some of our fundamental knowledge of the alimentary tract, has furnished the basis for an intelligent appreciation of the points at issue in relation to the intestine.2 According to these findings, if the vessels supplying parts of the alimentary canal are ligated, the tissues become edematous and purple, but may not be completely anemic. After this condition has persisted for six or seven hours such regions may recover normal activities, and, on being examined histologically, show nervecells with normal appearance. If complete anemia is produced by suitable compression, the condition may last as long as three hours and normal motility may still be restored. A persistence of compression anemia for three and one-half hours or longer, however, almost invariably results in loss of function and disappearance of nerve-cells in the compressed parts. Cannon and Burket point out that the continued existence of the cells of the myenteric plexus after three hours of complete anemia—two hours longer than the cells of the sympathetic ganglia—reveals them as the most hardy nerve-cells thus far found in the body. Incidentally, it is worthy of emphasis that the concomitance of persistence or loss of function with persistence or destruction of nerve-cells lends new support to the contention that the spontaneous contractions of the alimentary canal are of nervous origin. 1. Magnus R.: Arch. f. d. ges. Physiol., 1904, cii, 362. 2. Cannon, W. B., and Burket, I. B.: The Endurance of Anemia by Nerve-Cells in the Myenteric Plexus, Am Jour. Physiol., 1913, xxxii, 347. JAMA. 1913;61(25):2244.

Section Editor: Jennifer Reiling, Assistant Editor.

JAMA December 18, 2013 Volume 310, Number 23

Copyright 2013 American Medical Association. All rights reserved.

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The resistance of various nerve-cells to anemia.

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