Abstract
Purpose :
The calcitonin gene-related peptide (CGRP) family of neuropeptides contains besides CGRP, adrenomedullin, amylin and calcitonin (CT). They share receptor components and structure, and have several similar biological actions. The receptors consist of either calcitonin receptor like-receptor (CLR) or calcitonin receptor (CTR) which for function needs an accessory protein, Receptor Activity-Modifying Proteins (RAMPs) 1-3. These define the receptor subtype and can interact and produce a number of different effects on ligand binding, signal transduction and receptor trafficking. It is discussed if amylin could trigger migraine, like CGRP. It has previously been shown that release of CGRP can be seen in migraine patients, who also experience different visual phenomena. Therefore, it is vital to understand the role of RAMPs and the respective ligands in various parts of the retina.
Methods :
Single and double immunohistochemistry were applied on frozen sections of adult rat retina using primary antibodies against amylin, CT, CGRP, RAMP1, RAMP2.
Results :
Amylin was mainly found in the plexiform layers, CT in retinal vessel walls and CGRP in the nerve fiber layer, ganglion cell layer and in some amacrine cells. RAMP1 was expressed in the nerve fiber layer and RAMP2 in the neuronal nuclei. We did not with double-labelling find co-localizations of the RAMPs and ligands in the retina.
Conclusions :
Little is known about how CT and Amylin bind their receptors. Our data show that rat retina expresses RAMP1 and RAMP2, and thereby making up for possible functional receptors for Amylin/CT/CGRP in the retina.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.