AMINES DERIVED FROM AMINO-ACIDS 187 



effect upon blood-pressure about one-twentieth of that exerted by 

 Adrenaline. When injected intravenously it causes a rapid and pro- 

 nounced rise in blood-pressure which is somewhat more prolonged 

 than the rise which is caused by injections of adrenaline. Unlike 

 adrenaline, how r ever, tyramine does not cause any vasoconstriction 

 when applied locally to mucous surfaces, and large doses fail to produce 

 the glycosuria which results from adrenaline-poisoning. Tyramine, 

 furthermore, has a decided action upon the uterus, causing the non- 

 pregnant uterus to relax while the pregnant uterus is stimulated to 

 contraction. The glands which are innervated by the sympathetic 

 system are stimulated by tyramine. 



It has been considered possible that since tyramine may be produced 

 in vitro from Tyrosine by the action of fecal bacteria, the presence of 

 this substance in the large intestine and its absorption may be respons- 

 ible for pathological conditions in which high blood-pressure is a 

 leading symptom. As in the case of adrenaline, prolonged adminis- 

 tration of tyramine leads to renal and vascular lesions similar to 

 those which so generally accompany persistent arterial hypertension 

 in man. 



Indolethylamine is not so potent as tyramine and differs from it 

 in several details of its action, notably in giving rise to muscular 

 tremors or even convulsions, due to a transient stimulation of the 

 central nervous system. Indolethylamine has also a direct stimula- 

 tory action on smooth muscle-fibers, which is especially marked in the 

 arterioles of the iris and the uterus. 



Among the Diamines, Putrescine and Cadaverine are of historic 

 interest as they were among the earliest putrefaction-bases to be 

 isolated, definitely characterized and identified. They are, however, 

 comparatively innocuous substances, having very slight physiological 

 activity and in common with other diamines, but in contrast to the 

 monamines, they cause a fall in blood-pressure when they are injected 

 intravenously. They occur in the urine in cases of cystinuria, their 

 presence indicating a defective power of the tissues to deaminize 

 amino-acids. 



Agmatine has a direct action upon the muscular tissues of the 

 uterus, inducing contractions; it is, however, very much less potent 

 in this respect than Ergamine which, with Ergotoxine and Tyramine is 

 the active principle of the pharmaceutical preparations of ergot. 



Ergot is a parasitic fungus, Claviceps purpurea, which grows on 

 diseased rye, and has been employed from very ancient times to cause 

 contractions of the uterus. The amines which it contains are undoubt- 

 edly produced by this fungus, as they are by other fungi and bacteria, 

 by decarboxylization of the corresponding amino-acids. Ergamine 

 stimulates unstriated muscle-cells directly, inducing especially powerful 

 contractions of the uterus, but also stimulating smooth-muscle fibers 

 in other organs, for example the stomach and intestine and the con- 

 strictor muscles of the pupil of the eye. When dissolved in physio- 



