Abstract
Meltzer and Auer 1 showed that subcutaneous injections or instillations of epinephrin have no effect upon the normal pupil of the cat and rabbit, Ephedrine and cocaine, however, produce mydriasis even in normal animals. Ergotoxin, or ergotamine, are said to cause miosis in dogs and cats and mydriasis in rabbits.
In guinea pigs the instillation of a few drops of epinephrin hydrochloride, 1:1000, causes a maximal dilatation of pupils of normal animals and of animals whose cervical sympathetic has been cut below the superior cervical ganglion. Ordinary doses of arecoline and physostigmine do not constrict the pupil dilated by epinephrin. There is a complete loss of light reflex. Ephedrine and cocaine behave exactly like epinephrin.
Ergotamine tartrate administered by instillation into the conjunctival sac produces mydriasis. But injection of the drug into the anterior eye chamber causes, after an initial dilatation, constriction of the pupil, which lasts for at least 12 hours. The pupils constricted by ergotamine do not react to other sympathomimetic drugs, but do respond to atropine.
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