Cells use 'bioelectricity' to coordinate and make group decisions

Summary

While Galvani was later proven wrong in the details, he wasn’t totally off. Virtually every cell on every branch of the tree of life expends a hefty chunk of its energy budget — in some cells, more than half — on maintaining a voltage across its membrane. The voltage difference that results, called the membrane potential, stores potential energy that can be released later. It’s like the pressure behind a dam: Gravity tugs water downhill, and dams store energy by holding water at the top of a hill. Like gravity, the electrochemical force tugs charges “downhill” — positive charges stream toward negative charges and vice versa in electrical currents. Blocking that flow, for example with a cell membrane, stores up electrical potential energy. The electric currents that pour from our wall sockets are streams of electrons. In cells, “it’s quite similar, but not exactly the same,” said Elias Barriga, who studies tissue biophysics at the Dresden University of Technology. “We are fueled by ions.” Ions are atoms or molecules that carry charge because of extra or missing electrons, which give them negative or positive charges, respectively. They can enter and exit cells only through specialized protein channels and pumps. Just as hydroelectric plants can use surplus energy to pump water back up into the reservoir for later use, cells use their chemical energy to pump ions “uphill” against the electric flow. By controlling the natural current and letting positive or negative charge build up on either side of their membranes, cells maintain their membrane potential. And if this energy is used or leaks away, cells can replenish it by expending more of their chemical energy. Elias Barriga has shown that frog embryos generate electrical fields to guide cell migration. The study of bioelectricity, formerly stranded in biology’s backwaters, is “coming back like crazy,” he said. Courtesy of Elias Barriga “You generate a potential: what’s inside versus what’s outside, a different conce...