Skip to main content
Download PDF
- Main
Pharmacologically Stimulated Pupil and Accommodative Changes in Guinea PigsPharmacologically Stimulated Accommodation in Guinea Pigs
Published Web Location
https://doi.org/10.1167/iovs.14-14096Abstract
Purpose
The guinea pig is being used increasingly as a model of human myopia. As accommodation may influence the effects of manipulations used in experimental myopia models, understanding the accommodative ability of guinea pigs is important. Here, nonselective muscarinic agonists were used as pharmacological tools to study guinea pig accommodation.Methods
Measurements were made on 15 pigmented guinea pigs. For in vivo testing, animals were anesthetized and, following baseline measurements, 2% pilocarpine was applied topically. Measurements included A-scan ultrasonography, optical coherence tomography (OCT) imaging, corneal topography, and refraction. In vitro lens scanning experiments were performed using anterior segment preparations, with measurements before and during exposure to carbachol. Anterior segment structures were examined histologically and immunohistochemistry was done to characterize the muscarinic receptor subtypes present.Results
In vivo, pilocarpine induced a myopic shift in refractive error coupled to a small, but consistent decrease in anterior chamber depth (ACD), a smaller and more variable increase in lens thickness, and a decrease in pupil size. Lens thickness increases were short-lived (10 minutes), while ACD and pupil size decreased over 20 minutes. Corneal curvature was not significantly affected. Carbachol tested on anterior segment preparations in vitro was without effect on lens back vertex distance, but did stimulate pupil constriction. Immunohistochemistry indicated the presence of muscarinic receptor subtypes 1 to 5 in the iris and ciliary body.Conclusions
The observed pilocarpine-induced changes in ACD, lens thickness, and refraction are consistent with active accommodation in the guinea pig, through cholinergic muscarinic stimulation.Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.
Main Content
For improved accessibility of PDF content, download the file to your device.
Enter the password to open this PDF file:
File name:
-
File size:
-
Title:
-
Author:
-
Subject:
-
Keywords:
-
Creation Date:
-
Modification Date:
-
Creator:
-
PDF Producer:
-
PDF Version:
-
Page Count:
-
Page Size:
-
Fast Web View:
-
Preparing document for printing…
0%