Subsensitivity to cholinoceptor stimulation of the human iris sphincter in situ following acute and chronic administration of cholinomimetic miotic drugs.

Abstract

1 Maximal pupillary miosis was obtained with single topical applications of 4 cholinomimetic drugs in therapeutic concentrations to normal human subjects. 2 When the pupil had recovered from the miosis, there remained a reduced light reflex response of 22.7% at 24 h after aceclidine, 18.0% at 31 h after pilocarpine, 10.3% at 48 h after physostigmine and 4.9% at 7 h after arecoline. 3 This reduced sensitivity to light was accompanied by an overshoot of the resting pupil diameter and, after aceclidine miosis, a reduced response to a second application of miotic. 4 Similar findings were observed in glaucoma patients following withdrawal of chronic pilocarpine therapy. 5 It is suggested that the slowly reversible after-effects of acute and chronic administration of cholinomimetic miotics can be explained by desensitization of iris sphincter cholinoceptors.

• Authors: S A Smith, S E Smith
• Journal: British journal of pharmacology (Br J Pharmacol) Vol. 69 Issue 3 Pg. 513-8 (Jul 1980) ISSN: 0007-1188 [Print] England
• PMID: 6105002 (Publication Type: Journal Article)

Chemical References

• Miotics
• Parasympathomimetics
• Quinuclidines
• Receptors, Cholinergic
• Pilocarpine
• Arecoline
• Physostigmine

Topics

• Adult
• Arecoline (pharmacology)
• Glaucoma (drug therapy)
• Humans
• Iris (drug effects)
• Light
• Miotics (pharmacology)
• Parasympathomimetics (pharmacology)
• Physostigmine (pharmacology)
• Pilocarpine (pharmacology)
• Pupil (drug effects)
• Quinuclidines (pharmacology)
• Receptors, Cholinergic (drug effects)
• Time Factors