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Identification and localization of muscarinic acetylcholine receptors in the ocular tissues of the chick
Author(s) -
Fischer Andy J.,
McKin Lise A.,
Nathanson Neil M.,
Stell William K.
Publication year - 1998
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19980316)392:3<273::aid-cne1>3.0.co;2-z
Subject(s) - retina , biology , muscarinic acetylcholine receptor , inner plexiform layer , ganglion , choroid , retinal pigment epithelium , ciliary body , microbiology and biotechnology , outer plexiform layer , neuroscience , ciliary ganglion , receptor , amacrine cell , anatomy , genetics
The purpose of this study was to characterize the distribution of muscarinic acetylcholine receptors (mAChRs) in the ocular tissues of hatched chicks. In the chick, different isoforms of these receptors have been detected in the brain, heart, and retina, and mAChRs in ocular tissues have been implicated in the pathogenesis of form‐deprivation myopia. However, the precise anatomical distribution of mAChRs within the retina, retinal pigment epithelium, choroid, ciliary body, and ciliary ganglion remains unknown. We used affinity‐purified, type‐specific antibodies directed to three different chick mAChR subtypes (cm2, cm3, and cm4) to detect receptor immunoreactivity in sections and extracts of these ocular tissues. We found cm2, cm3, and cm4 in the retina, retinal pigment epithelium, choroid, and ciliary body. Within the retina, cm2 was expressed in numerous amacrine and ganglion cells; cm3 was expressed in many bipolar cells and small subsets of amacrine cells; and cm4 was found in most, if not all, amacrine and ganglion cells. Each mAChR was localized to distinct strata within the inner plexiform layer that cumulatively form three broad bands that closely match previously described localizations of subtype‐nonspecific muscarinic ligand binding. Only cm3 was detected in the outer plexiform layer, and only cm4 was detected in the ciliary ganglion. We propose that each mAChR subtype has unique functions in each ocular tissue. J. Comp. Neurol. 392:273–284, 1998. © 1998 Wiley‐Liss, Inc.