122 MEDULLA 



0.7 mgm. of epinephrine. The pulse rate increased from 60 

 to 66 per minute; the systolic output from 71 to 120 cc. The 

 blood pressure rose from 103/68 to 120/64. These results 

 would indicate that in man the injection of epinephrine leads 

 to marked stimulation of the cardiac activity and a diminished 

 peripheral resistance. 243 



RESPIRATION 



Epinephrine, as noted by Oliver and Schafer, 480 causes some 

 diminution in the depth of respiration and at times a temporary 

 apnea. This effect disappears before the pressor action has 

 ceased to manifest itself. 383 That this apnea is not due to 

 vascular constriction in the medulla oblongata was shown by 

 Bouckaert 74 who found that it was not abolished in the cat 

 by previous administration of ergotoxine which, as we have 

 seen, abolishes the vascular constricting effect of epinephrine. 

 Mellanby and Huggett, 450 however, could not confirm this 

 result. In the dog, Langlois and Garrelon 383 found either a 

 diminution or an increase of respiration after epinephrine, de- 

 pending upon the state of the respiratory center, while Nice, 

 Rock, and Courtwright 470 found the effect to depend upon the 

 dose. Small doses stimulated, while large doses inhibited the 

 respiratory center. 



Small doses of epinephrine cause an increase in the depth of 

 respiration. In the cat a reduction is produced by 0.3 cc. of 

 a 1 : 1000 solution. These effects are independent of the ac- 

 companying blood pressure changes or vagotomy. 



Direct perfusion of the medulla has shown that epinephrine 

 acts directly on the respiratory center. Small doses cause an 

 increase in the depth and rate of respiration while large doses 

 diminish the depth and rate. 687 In man Hartman 270 also ob- 

 served an increase in rate from 24 to 42 per minute after the 

 intravenous administration of 1 cc. of a 1 to 50,000 solution of 

 epinephrine. 



It is now generally agreed that the apnoea which follows 



