776 THE ADRENAL GLANDS 



gland (in the cat), the mucous glands of the mouth and pharynx, the 

 gastric but not the pancreatic glands, can readily be shown to be 

 excited. In the case of the kidney the immediate effect is a diminution 

 of the urinary flow, due to constriction of the renal vessels. It has been 

 suggested by Cow 11 that one role of the suprarenal is to act as a regula- 

 tor of the urinary excretion. This observer has demonstrated, by ana- 

 tomical methods, direct vascular communications between the adrenal 

 medulla a,nd the kidney. That epinephrine actually gains the kidney 

 by these channels was shown by collecting and testing the blood after 

 its circulation through them. Blood collected, while the gland was ex- 

 cited reflgxly by sciatic stimulation, exhibited marked pressor action. 

 The work of Addis 12 and others shows that the excretion of urea is in- 

 creased under the influence of epinephrine in certain dilutions so that 

 though the urine may be diminished in quantity, its concentration is 

 raised. 



From these results as a whole, it is evident that the effect of epineph- 

 rine on muscles and glands is exactly the same as that which would be 

 produced by stimulation of their sympathetic nerve supply. This paral- 

 lelism of action between epinephrine and the sympathetic nervous sys- 

 tem becomes still more evident when we consider certain of the changes 

 in metabolism that follow administration of epinephrine. Injection of 

 epinephrine excites glycogenolysis in the liver so that hyperglycemia 

 and glycosuria become established, results which are also obtained by 

 stimulating the great splanchnic nerve. Intravenous injection of epineph- 

 rine causes the clotting time of the blood discharged from the liver 

 tb be very materially shortened, an effect also produced by stimulating 

 the splanchnic nerve. 13 



As in the case of the blood vessels, the above results are obtained even 

 after the sympathetic nerves to the part have been allowed to undergo 

 degeneration, from which it is concluded that the tissues elaborate some 

 substance which reacts with epinephrine. This substance may be pro- 

 duced either at the junction between the nerve and muscle the myo- 

 neural junction, or perhaps throughout the protoplasm itself. It is 

 called the receptor substance of JLangley, and is believed to react not 

 only with epinephrine, but also with various drugs. The receptor sub- 

 stance seems to increase, if not in amount, at least in sensitivity after 

 the removal of the nerve control. 



Ergotoxin, which is an amine obtained from ergot and also from cer- 

 tain of the products of histidine, has an action on the receptor substance 

 which is inhibitory and therefore antagonistic to that of epinephrine. 



The antagonistic action of ergotoxin affects the excitatory but not 

 the inhibitory actions of epinephrine. By using this drug we are en- 

 abled to show that, although the main effect of epinephrine on the tissue is 



