Bicarbonate (baking soda) makes sparkling water sparkle, causes bread to rise, absorbs odors and can be used for cleaning all sorts of stuff, including your teeth. In the body, it plays essential roles in buffering pH, aiding in digestion and neutralizing lactic acid produced during physical exertion. Much of the bicarbonate in our bodies comes from carbon dioxide, which is produced as a waste product in all cells, although some is ingested with carbonated beverages and certain types of foods.Now a new study from the Makino Laboratory at Massachusetts Eye and Ear/Harvard Medical School and colleagues at Salus University, describes how bicarbonate also alters how we see by modifying the visual signal generated by rod and cone photoreceptors that detect light. This study is described online in the Journal of Biological Chemistry.Within rods and cones, a small soluble molecule, cGMP, links photon absorption to the electrical activity of the photoreceptor. In the light, cGMP is destroyed and ion channels are closed. Positively charged sodium ions cease to enter the rod or cone and the membrane potential becomes more negative or hyperpolarized. Bicarbonate directly stimulates an enzyme called guanylate cyclase that synthesizes cGMP.

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From a practical standpoint, the wiring of the human eye – a product of our evolutionary baggage – doesn’t make a lot of sense. In vertebrates, photoreceptors are located behind the neurons in the back of the eye – resulting in light scattering by the nervous fibers and blurring of our vision. Recently, researchers at the Technion – Israel Institute of Technology have confirmed the biological purpose for this seemingly counterintuitive setup.”The retina is not just the simple detector and neural image processor, as believed until today,” said Erez Ribak, a professor at the Technion – Israel Institute of Technology. “Its optical structure is optimized for our vision purposes.” Ribak and his co-authors will describe their work during the 2015 American Physical Society March Meeting, on Thursday, March 5 in San Antonio, Texas.

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