GLUCOSE AND OXYGEN UTILIZATION IN SYMPATHETIC GANGLIA 113 



is going to free your pathway for the breakdown of amino acids and fats and 

 possibly other reserves. I think that one needs to consider these several possi- 

 bilities in trying to eliminate metabolic activity as a supporting mechanism for 

 electrical impulses. And in the case of the nerves, it seems to me perfectly possi- 

 ble, if you want to consider ATP as the energy reservoir, that one could make 

 a point of having a high reservoir in the nerve which can be pulled slowly for 

 activity. One may then get a stimulation of oxygen uptake because of the re- 

 moval of this ATP. One still would have enough reserve to keep activity going 

 for a long time in the absence of glucose. So I do not see that there is any incon- 

 sistency in the idea that the ATP level might be important in supporting nerve 

 functions. 



Dr. Larrabee: I do not believe there is any special answer. I think Dr. 

 McElroy has upheld me in emphasizing the speculative and hypothetical nature 

 of the way we are thinking. 



Dr. McElroy: The direct question is a case of whether you are inhibiting 

 metabolic activity when you inhibit nerve impulses. I did not see how you 

 could come to that conclusion. 



Dr. Larrabee: All I can say is that one cannot tell whether the effect is 

 primarily on an enzyme or not. 



Chairman Gerard: It seems to me the issue is very clear, as long as metab- 

 olism goes down directly proportional to the physiological response presumably 

 it is because units are falling out. 



Dr. Larrabee: I think that Mcllwain's proposal on this is probably in 

 point. What he said is essentially that as soon as we learn how various aspects 

 of metabolism change with activity then we can examine how these various 

 aspects change when we apply inhibitors. If the inhibitor is acting non-meta- 

 bolically then we can expect all aspects of metabolism to change in the same way 

 as if excitation were withdrawn. A metabolic inhibitor, on the other hand, 

 should cause a predominant effect on some particular portion of the metabolic 



system. 



Dr. Abood: We have been working with Dr. Geiger on his perfused cat 

 brain preparation and during glucose perfusion the cat is able to go on function- 

 ing, that is, with normal reflexes. We have been able to show that, during this 

 time, some things are disappearing in the brain. For example, we can show that 

 the microsomes in the region of the cortex vanish almost completely in some 

 areas. As you know microsomes are rich in lipids and proteins and on the basis 

 of what we find in the plug we cannot account for all that disappears from 

 the brain. So, apparently, some non-carbohydrate substance is being utilized. 



Dr. Larrabee mentioned that during glucose-free perfusion of these prep- 

 arations, activity gradually disappeared. We have noticed the same thing. 

 We have also shown that when the microsome fraction in certain areas 

 of the cortex goes down to 50% of the normal, electrical activity in the 



