GENERAL DISCUSSION 



Thomas J. Haley (University of California, Los Angeles, California): There 

 are four papers I would like to discuss. I was impressed with Dr. Brown's work, 

 and would like to point out that the great sensitivity of the nervous system in the 

 burro is to be contrasted with the high resistance of the blood platelet in the same 

 species. So we must be very careful in all evaluations as to whether we are dis- 

 cussing different species or different reactions within the same species. With regard 

 to Dr. Gasteiger's work, I was happy to hear that it was the preganglionic 

 cholinergic fiber which was involved. We have just completed some work on the 

 postganglionic endings of the vagus in the intestine. We took out the small intestine 

 in guinea pigs receiving 500 r, and over the 1st week postirradiation, including the 

 day of irradiation, we studied acetylcholine synthesis. There was no statistical 

 difference between the control and the irradiated intestine. Thinking this might 

 be a fluke, we then tested the gut under the same radiation conditions and used the 

 Trendelenburg preparation, which sets off the gastric reflex by increasing the 

 interluminal pressure. There was no difference in the response of the gut, pre- 

 irradiation or postirradiation, to hexamethonium or other ganglionic blockers or 

 to atropine. This would seem to indicate that neither the ganglion cells, which 

 synthesize acetylcholine in the gut, or the tenninal endings were affected at a 

 dose of irradiation which would kill 100% of the guinea pigs exposed. I was 

 very happy to hear about the results of Dr. Monnier's paper, inasmuch as one of 

 his former students, Dr. Gangloff, and I worked together for a couple of years 

 and came up with similar results in the cat. I might point out, however, that we 

 are in some disagreement with our Russian colleagues inasmuch as when we 

 shielded the head and irradiated the body of the animals, 3^ r sneaked through, 

 and we did not obtain any changes whatsoever in the EEG. In all other instances, 

 we got the same type of results that Dr. Monnier presented so beautifully this 

 morning. 



W. O. Caster (University of Minnesota, Minneapolis, Minnesota): After the 

 review of the Soviet literature, it is most interesting that we can also find in this 

 country changes in the miUiroentgen range. I would like to know a little more 

 about the neurology and neuroanatomy of Dr. Miller's atidiogenic seizure effect. 

 Does it have a human counterpart? The general characterization of some of the 

 effects was that we were seeing more of these things that tended to be like 

 psychotic tendencies in the human. Secondly, in line with some of Dr. Monnier's 

 good descriptions as a biochemist I would appreciate having someone hook this 

 together. Can you now put your finger on the centers and systems which might 

 perhaps be related to the dolorogenic seizure phenomenon described? The dose 

 levels certainly are the most interesting part of this paper. What was the lowest total 

 dose found to produce an effect? Your ability to detect variations in background 

 presumably due to fallout is particularly intriguing. Do you have any further 

 information on this particular matter? 



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