Abstract
This review summarizes about recent progress in the field of water channels (aquaporins) and volume-sensitive Cl-channels. Both channel proteins are deeply associated with the mechanism of water (liquid) permeation across the plasma membrane of cells. Aquaporins directly contribute to permeation of water molecules. So far, 10 kinds of mammalian aquaporins have been cloned and characterized. Each aquaporin has distinct characteristics in its biochemical, pharmacological and physiological aspects. Volume-sensitive K+ and Cl- channels are swelling-activated and involved in the cell volume regulation (regulatory volume decrease). Activation of the ion channels by hypotonic shock leads to the extrusion of water from cells. The swelling-activated Cl- channels in hepatocytes are inhibited by endogenous production of arachidonic acid. The cDNA coding volume-sensitive Cl- channels has not yet been found.
