THE ACTION OF CERTAIN NEW HISTAMINE DERIVATIVES

¹ From the National Institute for Medical Research, Hampstead, London, N. W. 3

The alkyl derivatives of histamine, produced by substitution on the amino-group, which have been available for examination, all show some activity of the histamine type. In the monomethyl derivative this activity is somewhat weaker on the blood vessels, somewhat stronger on the plain muscle of the uterus and intestine, than that of histamine itself. The ethylamino derivative has a weaker action (about 1:20) than histamine in all directions. As regards histamine actions, the dimethyl derivative occupies an intermediate position, having two-fifths to one-fifth of the activity of histamine; but it also shows in a weak form the nicotine action, which in the trimethylammonium base becomes predominant; the histamine action being, in this last case, reduced to, at most, a small trace.

Hydroxyethylglyoxaline has a weak and doubtfully specific stimulating action on plain muscle.