GLUCOSE AND OXYGEN UTILIZATION IN SYMPATHETIC GANGLIA 115 



utes after exposure in the rat there is a 12-15% decrease in the total nitrogen. 

 This is not a concentration change, but an actual change of amount and very 

 rapid in the presence of adequate nutrition. Also, I was a little taken aback 

 when Dr. Larrabee mentioned the fact that unruly enzyme systems might have 

 to deal with other than glucose metabolizers such as glutamine, since decarboxyl- 

 ase, deaminase and transaminase have been demonstrated, sometimes in 

 unusually high concentration, in the neural tissue, to channel substances other 

 than glucose into the tricarboxylic acid cycle to support oxidation, for example. 



I noticed that Dr. Grenell and others referred to grams wet weight or dry 

 weight in terms of their enzyme and other studies. There is a possibility that 

 since we are talking about cellular metabolism perhaps we should refer 

 to the actual cell density of the tissues we are studying. With Dr. Gordon, I 

 have developed a very simple little technique for actually enumerating the 

 number of neuron and non-neuron nuclei in various parts of the brain and I 

 would like to give you some comparable data which we have on a striate cortex. 

 There are a variety of forms. In the macaque and in two humans (a 16 yr. old 

 and a 77 yr. old), if we take the total nuclei per gram of wet tissue, which is the 

 usual reference (total nuclei, by actual count, is the neuronal nuclei plus the 

 glia nuclei) we find 10.3 for the macaque, 9.45 for the 16 yr. old woman and 

 9.10 for the 77 yr. old man. The neuronal nuclei per gram of wet striate cortex 

 were found to be 1.40 for the rat, 1.42 for the macaque, 1.75 for the young 

 woman and 1.47 for the older man. I think that possibly the cellular references 

 which can be obtained with extraordinary ease might be able to reveal some 

 significant variations in metabolic activity whereas a nitrogen reference might 

 not. For glia and endothelial nuclei, it is 88.7, 77.7 and 5.63. These are all 

 nuclei times 10 7 per gram wet striate cortex. One of the very surprising things 

 is the relative uniformity of the density of cells, neurons and glia per gram wet 

 striate cortex in, I would say, widely variant forms. 



Dr. Larrabee. These mishievous chaps have certainly grown since I tossed 

 them out! I do think that one thing to be remembered is that, whatever happens 

 in the cell in the absence of glucose, it cannot be ascribed to destruction of one 

 of the enzymes involved in glucose metabolism, for example, because glucose 

 uptake, lactate production, and oxygen consumption all return to the original 

 rates when glucose is restored. The capacity for impulse conduction and syn- 

 aptic transmission, nevertheless, is not restored. 



Dr. Folch-Pi: I don't think we have mentioned that glucose is not what it 

 used to be and certainly biologists are not what they used to be. Because here 

 we are forgetting one important fact and that is the oxygen. Mcllwain cuts a 

 slice of cortex, puts it in the icebox, comes the next day and he still gets good 

 oxygen potential, which does not mean he gets activity for hours. He doesn't 

 claim that. I would like somebody to comment on when we stop dealing with 

 a live brain (in the same sense as a live muscle) and when do we just have the 



