DRUGS ACTING ON THE NERVOUS SYSTEM 43 



III. — Drugs Acting on the Nerves. 



The nerve terminations, rather than their trunks, are 

 influenced by drugs. 



(A) Drugs influencing peripheral sensory nerve-endings, 



(1) Stimulating sensory nerve terminations. — Counter- 

 irritants. (See p. 62.) 



General Uses. — They are applied externally (mustard 

 and heat) to stimulate the heart and respiration in heart 

 failure, shock and collapse. 



(2) Depressing sensory nerve-terminations. — These include 

 local sedatives or anodynes, which lessen sensation ; and 

 local anaesthetics, which abolish sensation. 



Uses. — The local anodynes are employed to relieve pain 

 of an inflammatory, rheumatic or neuralgic character, and 

 itching. The local anaesthetics are employed to prevent 

 pain in surgical operations. 



(B) Drugs inflttencing peripheral motor nerve-endings. 



(1) STIMULATING MOTOR NERVE-TERMINATIONS. 



Strychnine Nicotine 



Pilocarpine Pyridine 



Aconite 



(3) DEPRESSING MOTOR NERVE-TERMINATIONS. 



Curare Cocaine 



Conium Camphor 



Amyl nitrite Prussic acid 



Atropine Nicotine, and many others 



