THE NATURE OF THE PILOMOTOR RESPONSE TO ACETYL CHOLINE; SOME OBSERVATIONS ON THE PHARMACODYNAMICS OF THE SKIN

¹ From the Department of Pharmacology and the Department of Medicine, Division of Dermatology, of the University of Chicago, Chicago

1. Intracutaneous administration of high dilutions of acetyl choline and of other drugs possessing nicotine-like action caused a strong, fleeting pilomotor activity in the vicinity of the injection.

2. In the human skin and in the tail of the cat, this response was abolished by sympathetic nerve degeneration, remained active in areas anesthetized by nerve block, and could be elicited in extirpated pieces of skin.

3. High dilutions (1:100,000 to 1:200,000) of local anesthetics inhibited the reaction when mixed with effective doses of nicotine or acetyl choline.

4. The influence of various other drugs upon this pilomotor response is described.

5. It is concluded that the pilo-erection is effected through an axon reflex involving the terminal ramifications of the post-ganglionic sympathetic fibers supplying the pilomotor muscles.

6. The receptor end of this axon reflex possesses several properties characteristic of autonomic ganglia.

7. Preliminary observations are cited concerning an accompanying axon reflex involving similarly the terminal branches of the nerves supplying the sweat glands.

8. Evidence is presented for the simultaneous occurrence of a third axon reflex, involving the branches of the sympathetic vasoconstrictor fibers.

9. It is concluded that nicotine and drugs with similar action, when injected intradermally, probably elicit axon reflexes involving the whole autonomic nerve supply of the skin.

10. It is suggested that these peripheral responses to nicotine may be useful as the basis of a test to demonstrate, first, nicotine-like action in drugs, and second, the integrity of the sympathetic nervous supply in the skin.