1. The retinal relaxing factor : update on an enigmatic regulator of the retinal circulation
- Author
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Bart Pauwels, Johan Van de Voorde, Charlotte Boydens, and Laura Vanden Daele
- Subjects
retina ,review ,FLICKERING LIGHT ,ARTERIOLES IN-VITRO ,Biology ,retinal relaxing factor ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Retina circulation ,PERIVASCULAR RETINA ,VASORELAXING FACTOR ,medicine ,Medicine and Health Sciences ,Animals ,Humans ,Rho-associated protein kinase ,vasorelaxation ,Endothelium-Dependent Relaxing Factors ,Retina ,NITRIC-OXIDE ,PROSTAGLANDIN SYNTHESIS ,BLOOD-FLOW ,Inward-rectifier potassium ion channel ,Microcirculation ,Retinal Vessels ,Retinal ,Adenosine ,Adenosine receptor ,MESENTERIC-ARTERIES ,Cell biology ,Vasodilation ,medicine.anatomical_structure ,Biochemistry ,chemistry ,ADENOSINE RECEPTOR ,ATP-INDUCED RELAXATION ,030221 ophthalmology & optometry ,Endothelium, Vascular ,Adenosine triphosphate ,retinal blood flow ,030217 neurology & neurosurgery ,medicine.drug - Abstract
The retinal circulation is regulated by different local factors and might include the retinal relaxing factor (RRF). This factor is found to be continuously released by the retina and relaxes smooth muscle cells. This review describes the current knowledge about the RRF. Despite many research efforts, the cellular source, identity, mechanism, and physiological role of the RRF remain largely unknown. Thus far, it seems that the RRF is a hydrophilic, thermostable, diffusible chemical messenger, which characteristics do not correspond with most well-known endogenous vasorelaxants. The RRF-induced relaxation seems to rely on activation of the inward rectifier K+ channels and the Rho kinase Ca2+ sensitization mechanism. Voltage-dependent K+ channels and plasma membrane Ca2+-ATPase might also be involved, whereas the involvement of cyclooxygenase is still a point of discussion. Furthermore, it appears that the RRF is involved in other relaxation pathways, namely those of hypoxia, adenosine, and adenosine triphosphate, hydrogen sulfide, c-aminobutyric acid, and dorzolamide.
- Published
- 2017