Chapter XIV 



NON-MAST CELL HISTAMINE: THE HIGH HISTAMINE 

 CONTENT OF THE PYLORIC MUCOSA 



ON our return from the Histamine Symposium in London, Dr. West 

 and I felt that it would be of interest to test some of the views which 

 had been expressed on the possible origins of the histamine in mast 

 cells. Instead we discovered a ' compartment ' of tissue histamine which is 

 neither contained within the mast cells, nor is it greatly susceptible to the action 

 of the chemical histamine-liberators. 



The experiment which disclosed this information was as follows. Three 

 groups, each of twelve rats, were given a five-day course of compound 48 80 

 to reduce their mast-cell histamine to a low level. Thereafter, for six days, the 

 first group received a daily intraperitoneal injection of 1 mg. histamine dihydro- 

 chloride, the second group received 1 mg. histidine daily, and the third group 

 were given appropriate injections of saline. The histamine and histidine were 

 themselves dissolved in saline; the volume of each injection was 1 ml. The 

 diet consisted of w Rat cubes' (North-Eastern Agricultural Co., Aberdeen) and 

 abundant drinking water. Histamine was estimated in four animals from each 

 group (a) before starting the course of compound 48 80, (b) at day five, at the 

 end of the course of compound 48 80, and (c) at day eleven during the recovery 

 period when the various groups had received histamine, histidine or saline 

 for six days following their initial depletion. Since it is generally believed that 

 the main source of tissue histamine is the histidine in the diet, we anticipated 

 that either, or both, groups receiving supplements would show a more rapid 

 restoration of tissue histamine than the controls. For the same reason we 

 included tongue, oesophagus, stomach (fundus and pylorus separately), 

 duodenum, ileum, caecum and liver for histamine assay at each stage of the 

 experiment. The results are expressed in Table XXI. 



Examination of the findings shows, in the first place, that neither the intra- 

 peritoneal injection of histamine nor histidine has greatly affected the recovery 

 rate of histamine in the tissues (a possible exception is the subcutaneous tissue 

 of the group receiving supplementary histidine). Secondly, the pattern of 

 depletion and recovery permits the various tissues to be grouped into three 

 categories. In the first group are the tissues rich in mast cells which we have 

 often examined in past experiments — ears, feet, subcutaneous connective tissue, 

 mesentery and omentum, to which may now be added tongue, oesophagus and 

 the fundus of the stomach: these all show a pronounced fall in histamine 

 content, followed by a partial recovery by day eleven of the experiment. In 



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