Distribution of histamine and substance 'P' in the wall of the digestive tract of the dog / by W.W. Douglas [and others].

Date:
[1951?]
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Licence: In copyright

Credit: Distribution of histamine and substance 'P' in the wall of the digestive tract of the dog / by W.W. Douglas [and others]. Source: Wellcome Collection.

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    [From the Proceedings of the Physiological Society, 17 February 1951.] Journal Physiology, Vol. 114. / Distribution of histamine and substance ‘P’ in the wall of the digestive tract of the dog. By W. W. Douglas, W. Feldberg, W. D. M. Paton and M. Schachter. From the National Institute for Medical Research, Mill Hill, N.W. 7 The histamine equivalent of the different layers of the dog’s digestive tract was determined by extraction with acidified saline, brief boiling, and assay on the atropinized guinea-pig’s ileum (Table 1). The results show that: (1) the oesophagus contains relatively little histamine; (2) the gastric mucosa of fundus and corpus about twice as much as that of the pyloric region (confirming Emmelin & Kahlson, 1944); (3) the histamine in the wall of the small intestine progressively decreases towards the ileum; all layers except muscularis mucosae share in this gradient; (4) in the wall of the small and large intestine, where the muscularis mucosae could be separated, it yielded a higher histamine equivalent than any other layer; (5) the muscularis externa always contained less histamine than the mucosa, whereas (6) the submucosa, although free from muscle and glands, contained relatively large amounts. Table 1. Average values from three dogs of histamine equivalent (fig. of base per g. fresh tissue) G.M. M.M. S.M. M.E. Whole wall Oesophagus (<- 28 ->) 8 17 Stomach Fundus («- 127 ->) 58 32 69 Corpus («- -100- ->) 100 25 69 Pyloric region (*- 60 ->) 48 14 27 Duodenum 89 128 74 40 89 Jejunum 88 124 51 26 74 Upper Ileum 54 143 35 26 64 Lower Ileum 32 110 31 19 50 Colon 9 143 29 7 44 Rectum 7 130 31 14 42 G.M. = glandularis mucosae; M.M. = ; muscularis mucosae; S.M. = submucosa; M.E. = muscularis externa. In addition to histamine a substance resembling substance ‘ P ’ of von Euler & Gaddum (1931) was found. There was little in oesophagus and stomach, but large amounts in the small and large intestine. These large amounts were mainly present in the two layers of the mucosa, particularly in muscularis mucosae, 5-10 mg. of which contained as much activity (on the atropinized guinea-pig’s gut after mepyramine and on the blood-pressure of the atropinized rabbit) as 1 mg. of a purified sample of substance ‘ P ’ kindly supplied by von Euler. REFERENCES Emmelin, N. & Kahlson, G. S. (1944). Acta physiol. Scand. 8, 289. von Euler, U. S. & Gaddum, J. H. (1931). J. Physiol. 72, 74.