THE PRESSOR BASES 



585 



Epinephrine 



Tyrainine (p-hydroxyphenyl 

 ethylamine) 



Histamine (/3-iminazolyl- 

 ethylannine) 



+ means rise of blood pressure or constriction, 

 amine may have a pressor effect in some animals. 



the opposite; the last-named 



Another difference is the production of severe urticarial reactions by 

 histamine introduced into the skin, while tyramine and epinephrine 

 both cause local blanching (Sollnian and Pilcher).''- 



Thcse substances have all been found in putrid protein materials, 

 produced by the action of anaerobic bacteria, and possibly they are 

 formed in the intestines, as colon bacilli are able to form histamine 

 from histidine.*'^ Para-hydrox3'-phenyl-ethylaniine is also one of the 

 active constituents of ergot, and has been found in the salivary gland 

 of cephalopods, where it functions as a venom in paralyzing the prey. 

 Beta-iminazolyl-ethylamine is said to be the most important con- 

 stituent of ergot. It has been found regularl}^ present in the intestinal 

 mucosa, presumably formed by intestinal bacteria. According to 

 AbeP^ histamine is widely distributed in all animal tissues, organ 

 extracts, Witte's peptone, etc., or at least some substance that has simi- 

 lar physiological effects. He believes it to be especially abundant in 

 the hypophysis and to form its chief active constituent, but histamine 

 exhibits distinct differences from pituitrin. Hanke and Koossler^^" 

 however, have shown, by using purely chemical methods, that the 

 perfectly fresh hypophysis contains no histamine. They could further 

 demonstrate that peptone prepared from fibrin under aseptic condi- 

 tions is free from histamine yet capable of producing typical peptone 

 shock. 



All these amines are detoxicated by the liver, and hence have little 

 effect when given by mouth. ^^ It is probable that no inconsiderable 

 amounts are taken in our food and formed in the intestines every day 

 (Abel). Their detoxication is accomplished by deaminization and 

 oxidation, the resulting carboxylic acids being excreted or burned. 

 Therefore it is not certain whether pressor bases formed in the intes- 

 tines ever have any pathological effect, but it is quite possible that 

 outside the portal territory various infections maj^ give rise to pressor 



" Jour. Pharm., 1917 (9), 391. 



63 Koessler and Hanke, Jour. Biol. Chem., 1919 (39), 539. 



" Jour. Pharmacol., 1919 (13), 243. 



«^»Jour. Biol. Chem., 1920. 



6" See Guggenheim and LoefBer, Biochem. Zeit., 1916 (72;, 325. 



