Permanent alterations in muscarinic receptors and pupil size produced by chronic atropinization in kittens

Journal Article · Wed Feb 01 00:00:00 EST 1984 · Invest. Ophthalmol. Visual Sci.; (United States)

OSTI ID:6915540

Smith, E L; Redburn, D A; Harwerth, R S; Maguire, G W

Chronic mydriasis was induced in six kittens (four monocular, two binocular) and two adult cats (both monocular) by the daily topical application of atropine. Both the kittens and the adult cats were atropinized for a 13-week period with the treatment regimen beginning at the time of eye opening for the kittens. Pupil size measurements, obtained 1 year after the atropinization were discontinued, revealed that, although the pupils of the adult cats were normal, the pupils of the kittens' treated eyes were consistently smaller than pupils in control eyes. The status of the muscarinic receptors in the kittens' irides was investigated using /sup 3/H-QNB binding assays. In comparison with iris muscle homogenates from the control eyes, those from the treated eyes demonstrated an eightfold increase in the number of receptor binding sites. The results indicate that pupil size can be altered permanently by chronic mydriasis initiated early in the life of a kitten and that the permanent change in pupil size may result, in part, from a type of permanent supersensitivity response in the muscle following chronic blockade of muscarinic transmission by atropine.

• Research Organization: College of Optometry, University of Houston, University Park, TX
• OSTI ID: 6915540
• Journal Information: Invest. Ophthalmol. Visual Sci.; (United States), Vol. 25:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
RECEPTORS
ATROPINE
CATS
ONTOGENESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALKALOIDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
DRUGS
ESTERS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
NEUROREGULATORS
ORGANIC COMPOUNDS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
QUATERNARY COMPOUNDS
VERTEBRATES
550801* - Morphology- Tracer Techniques