THE SMOOTH MUSCLE ACTIONS OF EPINEPHRINE SUBSTITUTES VII. RESPONSES OF DENERVATED SMOOTH MUSCLES OF IRIS AND INTESTINE TO EPINEPHRINE, EPHEDRINE, AMPHETAMINE (BENZEDRINE) AND COCAINE

¹ From the Department of Pharmacology, School of Medicine University of Southern California

1. The iris of cats and rabbits was denervated by excision of superior cervical ganglion. Two weeks was allowed for nerve degeneration.

2. Mydriasis in the normal eye was caused by instillation of epinephrine, ephedrine, amphetamine (benzedrine) or cocaine.

3. Denervation of the cat's iris prevented mydriasis by ephedrine or cocaine. Amphetamine mydriasis persisted and epinephrine nephrine mydriasis was increased (sensitization).

4. Denervation of the rabbit iris prevented mydriasis by amphetamine or cocaine. Ephedrine mydriasis persisted and there was sensitization to epinephrine.

5. Sympathetic postganglionic denervation of the small intestine of cats, rabbits and monkeys was accomplished by section of one or more branches of the superior mesenteric artery, with accompanying nerves. Two weeks was allowed for nerve degeneration.

6. Such denervated loops of intestine exhibited a sensitization toward epinephrine but no alteration in response to ephedrine, emphetamine or cocaine.