PARASYMPATHETIC SENSITIZATION IN THE CAT'S EYE

Abstract

[longdash]The normal pupil of the cat reacts only slightly to the intraven. inj. of 5 mgs. of acetylcholine per kg. of body wt. Excision of the ciliary ganglion or intracranial section of the oculomotor nerve results in a marked acetylcholine sensitization of the iris sphincter. The magnitude of this sensitization is approx. the same whether the sphincter is de-nervated or decentralized. Sensitization of the iris sphincter reached a maximum within about 5 days and similar curves were obtained until about the 18th day. After this time the responses decreased until they reached a steady minimum within approx. 35 days. The recovery of acetylcholine sensitization following the instillation of physostigmine suggests that the loss of sensitization is associated with an increased choline esterase activity.