Histochemical Demonstration of Ascorbic Acid in the Locus Coeruleus of the Mammalian Brain

Abstract

Diehl and Neumann¹ have determined the content of ascorbic acid in the various portions of the human brain and found a characteristically high content in the autonomic centres (tuber cinereum and medulla oblongata). By means of the histochemical method the neurosecretory nuclei of the hypothalamus were reported to contain many silver granules due to reduction of silver nitrate by ascorbic acid^2–4. Although in the above chemical and histochemical reports particular attention was not paid to the locus coeruleus, the locus was recently found by a histochemical method (Shimizu et al. ^5,6) to demonstrate the pronounced activity of monoamine oxidase, and by several physiological investigations^7–9 to regulate respiration, as the pneumotaxic centres. As the locus coeruleus was thus supposed to display some autonomic (visceral) functions, which might be related to amine metabolism, we thought it reasonable to search for the histochemical presence of ascorbic acid in the locus coeruleus.