KAWAMURA, Y. 
DISCUSSION 
DR. MINARD: Is it not possible that theACH acts by cutaneous 
vasodilation, warming the skin and reducing the afferent input from 
the skin, whereas epinephrine might have the opposite effect? Is it 
possible that acetylcholine, instead of acting on the ascending retic- 
ular formation, might act peripherally by vasodilation in the skin, 
thereby reducing the thermoreceptor inflow to the center? 
DR. KAWAMURA: Yes, there may be two processes. One is the 
effect of the autonomic function on the vasomotor system; the other 
is the direct effect of these drugs on the central somatic system. I 
woidd guess that the effect is either on the autonomic or somatic 
central mechanisms and that they are more important in this case 
than the peripheral ones. 
DR. RODDIE: How was the acetylcholine given? 
DR. KAWAMURA: By injection into the femoral vein. 
DR. RODDIE: It is just that the action of acetylcholine in the 
bocfy is a very short one; it is destroyed very quickly. That was 
shown by the heart rate records. But the inhibition of shivering 
lasted for quite a long time, right until the end of the record. I 
wonder whether there was any other effect that acetylcholine might 
have. 
DR. STUART: I do not think he showed heart rate. He showed 
blood pressure dropping. 
DR. RODDIE: There was an EKG record, and it came back to 
normal whereas shivering was inhibited throughout the record. 
DR. FREEMAN: Also, acetylcholine passes very slowly across 
the blood-brain barrier so that unless one gave it by intrathecal in- 
jection into the purported centers one would find it hard to see how 
it could escape destruction by acetylcholinesterase in the blood. 
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