ADRENALINE (EPINEPHRIN, ADRENINE) 95 



It has lately been shown that the secretion of adrenaline is con- 

 trolled by the splanchnic nerves (Asher [1912], O'Connor [1912, 2], 

 Elliott [1912], Dale and Laidlaw [1912, 2]). Cutting these nerves 

 stops the secretion. The supra-renals may be exhausted by fright, by 

 tetrahydro-$-naphthylamine and by morphia, but if one of the 

 splanchnic nerves is cut, the gland on that side is not exhausted 

 (Elliott). Peripheral electrical stimulation of a cut splanchnic nerve 

 produces the same effects as an injection of adrenaline. An injection 

 of nicotine and other alkaloids also stimulates the gland to excrete 

 adrenaline (Cannon, Aub and Binger [1912], Dale and Laidlaw 

 [1912,2]). 



Asphyxia also increases the adrenaline secretion (Cannon and 

 Hoskins [1911-2]). The constriction of peripheral blood vessels on 

 stimulation of the splanchnic nerves (von Anrep [1912]) and the 

 effect of carbon dioxide on the vascular system (Itami [1912]) are 

 both due to increased secretion of adrenaline. 



Cannon and de la Paz [1911] were the first to show that the 

 secretion may be stimulated by emotion ; they placed a cat near a 

 barking dog and found that the blood from the cat's supra-renal vein 

 contained an increased amount of adrenaline, as shown by its action 

 on strips of muscle from the rabbit's intestine. It is possible that the 

 supra-renals obtained from slaughterhouses for this reason contain less 

 adrenaline than is normally present. Connected with this is emotional 

 glycosuria (Cannon, Shohl and Wright [191 1-2]). 



Nothing is known of the nature of the parent substance from 

 which adrenaline is derived. The base is obviously more closely re- 

 lated to tyrosine than to any other known constituent of protein, and 

 Halle [1906] has asserted that the adrenaline content of the supra- 

 renals is increased when they are incubated with tyrosine, but this 

 assertion has been disproved by E wins and Laidlaw [1910, i]. Abel- 

 ous and his pupils considered at one time that adrenaline is formed by 

 incubating supra-renals with muscle, but the increased pressor activity 

 of the mixture was later found to result from the meat alone, which 

 underwent putrefaction so that p-hydroxyphenyl-ethylamine was 

 formed (see p. 26). It has been suggested that adrenaline might be 

 derived from a di-hydroxyphenyl-methyl-serine (by decarboxyl- 

 ation), but for this there is not the slightest evidence. It should, how- 

 ever, be noted that Guggenheim [1913] has isolated the amino-acid 

 3 : 4-dihydroxyphenylalanine, (OH),,C a H 8 . CH 2 . CH(NH 2 ) . COOH, 

 from the pods of Vicia Faba. 



