AMINES DERIVED FROM PROTEIN 29 



very broadly, indolethylamine (with two nitrogen atoms of which only 

 one is basic) has a physiological action intermediate between that of 

 the sympathomimetic monamines such as p-hydroxy-phenyl-ethylamine, 

 and the diamines, like iminazolyl-ethylamine. 



Ewins and Laidlaw [1913] have more recently studied the fate 

 of indolethylamine in the organism ; in the perfused liver the base is 

 converted into indole-acetic acid, a change quite comparable to the 

 transformation of p-hydroxy-phenyl-ethylamine into p-hydroxy- 

 phenyl-acetic acid (see p. 27). In dogs the indole-acetic acid is 

 however excreted in the urine in combination with glycine as indole- 

 aceturic acid C 8 H 6 N . CH 2 . CO . NH . CH 2 . COOH, mp. 94, forming 

 an orange red picrate which melts at 145. 



Among diamines /3-iminazolyl-ethylamine is the only one having a 

 cyclic structure, and it is by far the most active. Putrescine and 

 cadaverine have at most a very slight toxicity ; on intravenous injection 

 in the cat they lower the blood pressure. Agmatine has according to 

 Engeland and Kutscher [1910, l] a powerful action on the isolated 

 uterus, causing contraction, but Dale and Laidlaw [1911, p. 194] 

 state that agmatine does not make any significant contribution to 

 the activity of ergot and is only feebly active as compared with 

 /3-iminazolyl-ethylamine, also present in ergot. Thus 5 mgs. of 

 agmatine produced a much smaller effect on the cat's uterus than 

 O'l mg. of the latter base. 



The physiological action of ^-iminazolyl-ethylamine has been 

 investigated by Ackermann and Kutscher [1910, I] and more fully by 

 Dale and Laidlaw [1910, 191 1]. 1 According to the latter authors the 

 fundamental and characteristic feature of the action is a direct stimulant 

 effect on plain muscle, producing exaggerated rhythm or tonic con- 

 traction, according to the dose. The most sensitive plain muscle is 

 the non-pregnant uterus of some species and it is this reaction which 

 led to the identification of the base in ergot. A marked contraction 

 of the isolated uterus is produced by adding to the bath of Ringer's 

 solution sufficient of the base to give a concentration of I : 25,000,000 

 and the effect of I : 250,000,000 is often quite definite (compare 

 also Frohlich and Pick [1912] and Sugimoto [1913]). The muscular 

 coats of the bronchioles are also highly sensitive to the action of 

 /3-iminazolyl-ethylamine, especially in rodents, but not in the ox 

 (Trendelenburg [1912]). Baehr and Pick [1913, I] have studied the 

 effect on the musculature of the surviving guinea-pig's lung. Here 



1 Many scattered observations on its action occur in the pharmacological literature of the 

 last few years. 



