Amylin competes for binding sites of CGRP in the chamber angle and uvea of monkey, cat, and pig eye.
Calcitonin gene-related peptide (CGRP) binding sites have been identified previously in the eyes of monkey, cat, pig, and guinea pig. In this study, the ability of cat, human, and rat amylins to displace the binding of CGRP in the anterior part of the eye of monkey, cat, and pig was studied. The location and displacement of 125I-hCGRPalpha by amylins as concentrations of 1-1000 nM were studied in cryosections by autoradiography. In the monkey eye, cat and rat amylins were able to compete for the binding sites of CGRP in ciliary muscle and ciliary processes. In the cat eye, cat and human amylins clearly displaced CGRP binding from ciliary muscle, ciliary processes, iris, and chamber angle. Furthermore, rat amylin clearly displaced CGRP binding from ciliary muscle and ciliary processes. In the pig eye, cat, human, and rat amylins competed for the binding sites of CGRP in ciliary muscle, ciliary processes, iris, and limbal conjunctiva. Specific amylin receptors or the possible physiological role of amylin in the eye have not hitherto been reported. It seems, however, that amylin can bind to ocular CGRP receptors and thus probably plays a role in the regulation of the same functions as CGRP, (e.g., aqueous humor outflow).
Alajuuma
Päivi
P
Santen Oy, Tampere, Finland, and Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland. paivi.alajuuma@santen.fi
Oksala
Olli
O
Uusitalo
Hannu
H
D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D000867:Anterior Chamber / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D001667:Binding, Competitive / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D002415:Cats; D003228:Conjunctiva / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005629:Frozen Sections; D015870:Gene Expression; D006168:Guinea Pigs; D000882:Haplorhini; D006801:Humans; D007457:Iodine Radioisotopes / Q000737:chemistry / Q000378:metabolism; D058228:Islet Amyloid Polypeptide; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D013045:Species Specificity; D013552:Swine; D014602:Uvea / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
D000682:Amyloid; D007457:Iodine Radioisotopes; D058228:Islet Amyloid Polypeptide; D015740:Calcitonin Gene-Related Peptide