LIM, T. P. K. 
DR. HEMINGWAY: Anesthetics cause the skin temperature to 
go up very quickly, and it stays at certain elevated levels for a long 
period of time. Thus, it would seem that the cutaneous vasomotor 
response is so sensitive to anesthetics that they would seriously 
interfere with skin temperature measurements. 
DR. FREEMAN: There is one thing about your work that bothers 
me a great deal and makes me wonder about its relevance to normal 
processes. This is the high temperatures that you have to use to 
activate whatever you are stimulating. This has been my experience 
also. In order to get panting, or, for that matter, vasodilation in an 
anesthetized cat, you have to heat above the level which we ordinarily 
consider to be harmful to the brain. That is, above 42 C, which is 
so high that the response will decay if you maintain it for any length 
of time. Furthermore, if you try to get it twice or three times, you 
may get it the second time, never the third. This is associated with 
a marked disturbance of the animal. His pulse rate will usually go 
way down, his blood pressure will go down, his nocioceptive reflexes 
will disappear, and his muscle tone disappears completely; he is 
completely placid, and there is a very slow recovery period there- 
after. I think what this thing represents is some form of brain 
damage which may be related to manifestations you see in sunstroke. 
DR. LIM: With our dosage of anesthesia, as shown in the first 
figure, the temperature threshold in both central and peripheral 
areas is somewhere around forty-one. I would think of forty-two or 
forty-three degrees as being high, but we were using forty-one 
degrees centigrade in the panting studies. 
DR. FREEMAN: There is an interesting history of this so-called 
central response. In the first clear distinction of central versus 
peripheral heating by Roche", somewhere back around 1898, he de- 
fined central panting more in terms of its overwhelming durability 
in the face of anoxia. He set 40.7 C as a specific level of an emer- 
gency reaction. When panting did occur at this level, it would per- 
sist in the face of anoxia or asphyxia for a period of two, three, or 
even four minutes, whereas panting induced by external heating in an 
intact animal would be interrupted in a matter of thirty seconds or 
so. Now, most people that have tried to get this central phenomenon 
find that it is dependent upon the type of anesthesia being used. For 
example, Magoun published a short statement some two years after 
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