102 MEDULLA 



action on the cord. As Watanabe 657 showed, small doses of 

 strychnine do not cause an augmentation in the rate of epi- 

 nephrine secretion. Moderate doses (| to 3 mgms. per kilo 

 of body weight) cause an increase of four to five times the 

 normal rate of secretion. 



Other centrally acting convulsive drugs also cause a marked 

 discharge of epinephrine when injected in doses below the 

 convulsive level. 590 Thus picrotoxin 624 is more effective than 

 strychnine in stimulating epinephrine secretion. Santonin, in 

 sub-convulsive doses, camphor, in convulsive doses, caffein, 658 

 theobromine and guanidine 604 also cause a discharge of epi- 

 nephrine from the adrenals. All of the above mentioned drugs 

 apparently act by stimulating the higher centers controlling 

 epinephrine secretion. 637 



Sympathetic paralyzers. Nicotine, and its related drugs, 

 coniine, quaternary ammonium bases, etc. paralyze sympathetic 

 ganglia and, as might be anticipated, exert an analogous 

 action on the adrenal medulla. Gley 223 concluded that the 

 pressor effect of nicotine after destruction of the spinal cord 

 and bulb in dogs is practically entirely due to an increase in the 

 epinephrine output. Dale and Laidlaw 148 showed that the 

 effects of nicotine on the non-pregnant uterus of the cat and 

 on the eye after removal of the superior cervical ganglion are 

 in part due to the liberation of epinephrine for they do not 

 occur when this liberation is prevented. 



The action of nicotine and its related drugs is directly on the 

 medullary cells and is elicited in the denervated organ. As 

 Stewart and Rogoff 590 showed, after the injection of nicotine 

 there is first a marked increase in the output of epinephrine 

 which lasts for less than half a minute. This stimulation is 

 followed by a period of depression at the maximum of which 

 no epinephrine is liberated and finally the normal output is 

 gradually resumed. It is probable that nicotine not only 

 releases epinephrine from the medulla but also sets free the 

 epinephrine store of the extra-adrenal chromaphil tissues, for 



