Agre found a protein (aquaporin) in the kidney which he thaught to be the water channel. To test his hypothesis he took cells that contained the protein and cellls that did not contain the protein and placed them in a water solution. The cells with the protein absorbed water, and swelled. The cells without the protein did not react at all. This proved that the protein he found was indeed the water chammel evryone was looking for.
There is a positive charge in the channel so protons can not be leaked because they are repelled by the positive field. This is important because the difference in concentration between the outside and inside of the cellis important for the cellular enery storage system. Water molecules worm there way through by orienting themselves in the electron field in the channel. . Oxonium ions, H3o+ (refering to protons) are rejected because of there positive charge, so only water molecules are permitted to pass through.
