633 



It appeared, moreover, lIuU 0.06 uigr. of iiicoliii -j- 0.04 nigr. of 

 lobelin acted more forcibly upon the rise llian 0.1 mgr. of iiicotiii 

 or lobelin alone. This, then, is a case of ti-ne "BcKGi-potentiation". 

 This is illustrated by Fig. 1. 



JO. . 



1 0.0^ MA?'VeX\Axc 



Stijging = Rise. — Lobeline = Lobelin. 



Fig. 1. 



Nicotine = Nico tin. 



Bloodpressure, decapitated cat after attopin injection, a. 0,1 mgr. of nicotin 

 yields a rise of bloodpressure of 30 mm. Hg. ; b. 0,04 mgr. of lobelin +0,06 mgr. 

 of nicotin yields a rise 59 mm. Hg. 



When we endeavour to find an ex|)lanalion for this phenomenon, 

 it would seem as if, after the lobelin injection still some portion 

 of this substance is left behind in the cat's body, and (hat this, of 

 itself incapable of any action on the blood pressure, adds its effect 

 to that of the nicotin subsequently infused, so that this would seem 

 to be a case of "addition" and not of "potentiation". However, the 

 matter is not so simple, for if this were so, we might look for a 

 higher rise of the blood pressure after a second lobelin injection. 

 This is not the case. On the contrary the action of successive lobelin 

 injections upon the blood pressui-e is most often progressively dimi- 

 nishing. Besides, the hypothesis alluded to is disqualified by the 

 fact that a simultaneous injection of lobelin and nicotin is also 

 attended by a "potentiation'', as stated above. Lastly we have 

 ascertained whether other substances affording a rise of blood pressure 

 are "potentiated" by lobelin. This appeared not to be the case; 

 adrenalin e.g. yields perfectly similar effects before and after lobelin. 



Ultimately we have tried to make out whether, conversely, the 

 nicotin could potentiate the lobelin. The result negatived the suppo- 

 sition. With regard to the rise of blood pressure the effect of lobelin 

 after nicotin is not increased, even diminished. 



So far as we are able to judge the potentiating efïect of lobeljn 

 for nicotin is specific. It is analogous to the re-in forcing effect exerted 



