THE MAST CELLS 



N hydrochloric acid showed histamine activity on the isolated guinea pig ileum 

 and on the blood pressure of the atropinized cat. Prior removal of the excess 

 trichloracetic acid from the solution by ether extraction merely reduced the 

 intensity of the fast-running spot. When an eluate of this fast-running spot 

 (R F =0-65) was re-run in the same solvent as before, the histamine now 

 remained entirely in its lower location (R F =0-1 1 ). 



Further experiments showed that at least three factors are involved in the 

 migration of histamine to the fast-running spot, namely: (1) the concentration 

 of trichloracetic acid; (2) the concentration of histamine; (3) the presence of a 

 basic amino-acid. First, pure histamine acid phosphate in water forms a compact 

 spot at R F =0-11, but with increasing concentration of trichloracetic acid 

 a 'trail' of histamine moves up the paper as far as the R F =0-65 area. This is 

 not a mere pH effect, for histamine in 0-33 N hydrochloric acid or in 10 per 

 cent aqueous acetic acid does not migrate in this way. Trifluor-acetic acid 

 resembles trichloracetic acid in its mobilizing effect on histamine, recalling the 

 similar effect of these acids on the chromatographic behaviour of adrenaline 

 (Shepherd and West, 1952). Removal of the excess acid from these solutions 

 by ether extraction concentrates the histamine into a single compact spot at 

 R F =0-11. Secondly, when the strength of the trichloracetic acid is kept 

 constant, any increase in concentration of histamine in the mixture is followed 

 by increased upward trailing from the slow-running spot. Thirdly, for complete 

 separation of the two spots, the presence of at least one basic amino-acid is 

 necessary. Thus, when an artificial mixture is made up containing pure histamine, 

 trichloracetic acid and arginine, lysine or ornithine, the chromatographic 

 pattern now exactly resembles that seen with tissue extracts, the histamine 

 being divided between the two spots, R F =0-11 and R F =0-65; ether extraction 

 of this mixture simply reduces the intensity of the fast-running spot. When all 

 three amino-acids are present in the mixture, the chromatogram shows inversion, 

 only the upper (fast-running) spot now appearing on the paper. 



It is thus possible that the remarkable ability of trichloracetic acid to 

 extract histamine from tissues is related not only to its coagulative effect on 

 protein but also to its participation in a loose complex containing histamine 

 (probably as the trichloracetate) and basic amino-acids. Detailed analysis of 

 the original tissue chromatogram shows that arginine and lysine are in fact 

 present and trail behind the fast-running spot of histamine. 



Phospholipid content 



The hydration of the mast granule by water, and especially by water con- 

 taining alkali, invites comparison with other biological systems which react 

 in similar fashion. Among these, the curious formation of 'myelin figures' 

 by the fatty material of nerve sheaths or by the lipoidal walls of plant cells and 



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