Modes of Accessing Bicarbonate for the Regulation of Membrane Guanylate Cyclase (ROS-GC) in Retinal Rods and Cones
| Autor: | Alexandre Pertzev, Michael A. Sandberg, Rameshwar K. Sharma, Polina Geva, Tomoki Isayama, Clint L. Makino, Teresa Duda |
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| Rok vydání: | 2018 |
| Předmět: |
retina
genetic structures Gene Expression Ambystoma Tissue Culture Techniques chemistry.chemical_compound Mice 0302 clinical medicine Retinal Rod Photoreceptor Cells Chlorocebus aethiops Carbonic anhydrase inhibitor Carbonic Anhydrase Inhibitors Cyclic GMP Carbonic Anhydrases 0303 health sciences General Neuroscience General Medicine New Research cone Recombinant Proteins receptor guanylate cyclase Second messenger system COS Cells Retinal Cone Photoreceptor Cells Sensory and Motor Systems rod Acetazolamide Intracellular medicine.drug Visual phototransduction medicine.drug_class Bicarbonate Carbonic anhydrase II Receptors Cell Surface bicarbonate visual transduction 03 medical and health sciences Extracellular medicine Animals Vision Ocular 030304 developmental biology Cell Membrane Carbon Dioxide Bicarbonates chemistry Guanylate Cyclase 8.1 Biophysics Cattle sense organs 030217 neurology & neurosurgery |
| Zdroj: | eNeuro |
| ISSN: | 2373-2822 |
| Popis: | The membrane guanylate cyclase, ROS-GC, that synthesizes cyclic GMP for use as a second messenger for visual transduction in retinal rods and cones, is stimulated by bicarbonate. Bicarbonate acts directly on ROS-GC1, because it enhanced the enzymatic activity of a purified, recombinant fragment of bovine ROS-GC1 consisting solely of the core catalytic domain. Moreover, recombinant ROS-GC1 proved to be a true sensor of bicarbonate, rather than a sensor for CO2. Access to bicarbonate differed in rods and cones of larval salamander,Ambystoma tigrinum, of unknown sex. In rods, bicarbonate entered at the synapse and diffused to the outer segment, where it was removed by Cl--dependent exchange. In contrast, cones generated bicarbonate internally from endogenous CO2or from exogenous CO2that was present in extracellular solutions of bicarbonate. Bicarbonate production from both sources of CO2was blocked by the carbonic anhydrase inhibitor, acetazolamide. Carbonic anhydrase II expression was verified immunohistochemically in cones but not in rods. In addition, cones acquired bicarbonate at their outer segments as well as at their inner segments. The multiple pathways for access in cones may support greater uptake of bicarbonate than in rods and buffer changes in its intracellular concentration. |
| Databáze: | OpenAIRE |
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