418 IMMUNO-CATALYSIS 



motility and tone of stomach and intestine, and cause the relaxation of 

 their sphincters; contraction of the urinary bladder and relaxation 

 of the trigone and sphincter; and increased secretion of salivary and 

 lachrymal glands. A very important action of acetylcholine as of 

 cardiac vagal impulses is the slowing of the heart rate or the production 

 of auriculo-ventricular (A-V) block. This is accomplished by a de- 

 pression of the sino-auricular (S-A) node which initiates the heart beat 

 or auriculo-ventricular node which transmits the impulse from auricle 

 to ventricle. These are reactions which are accentuated in anaphylactic " 

 shock. 



e. Effects of Administered Acetylcholine in Man. A study dealing 

 with the autonomic, sensory and motor responses in man to injections 

 of acetylcholine has been reported (Harvey, Lilienthal and Talbot, 

 1941). Immediately after injection into the brachial artery the arm 

 below the elbow became flushed, warm and sweated profusely. These 

 responses persisted for 10 to 15 minutes then slowly waned. The injec- 

 tion was followed immediately by excruciating pain coursing down the 

 forearm into the palm and fingers. The character of the pain was 

 variously described as "burning," "tearing," or "tingling." Simultane- 

 ously with the development of pain in the injected arm the grip 

 power of the fingers and hand was greatly reduced so that only the 

 most feeble and partial flexion of the fingers could be effected 

 voluntarily. There was complete recovery of normal motor power 30 

 to 60 seconds after injection. There was no constant synchronized 

 movements in the fingers or hand following the injection of acetyl- 

 choline. In one subject, there developed a brief movement of the 

 fingers and hand resembling the carpal spasm of tetany. In four sub- 

 jects, there appeared in the relaxed palmar and forearm muscles 

 brief localized twitches of insufficient tension to produce more than a 

 slight movement of the fingers. 



The motor phenomena of paresis and fasciculation occurred only 

 transiently and feebly with the doses of acetylcholine which were em- 

 ployed. With prostigmine, however, these effects were much more pro- 

 longed and profound. It was believed that the prostigmine paresis 

 results from the inhibition of cholinesterase which permits the con- 

 centration of acetylcholine to rise to a paralyzing level. 



The observed eff"ects of intra-arterially injected acetylcholine in man 

 upon the sweat glands and the peripheral vascular bed was believed 



