Great minds think alike The recently cloned gene for the rat epithelial Na+ channel turns out to be related to nematode genes, mutations in which affect mechanosensation and cause neurodegeneration.

Despite the recent boom in the ion channel cloning indus- try, two classes of channel have until recently eluded the grasp of molecular biollogists. One of these two classes consists of ion channels regulated by mechanical stim- uli, such as sound or stretch, which have been detected in mechanosensory neurons and, surprisingly, in nearly all other cell types examined (including Eschericbia coli and yeast) [ 11. These mechanochannels have been im- plicated in sensory transduction and osmotic regulation. The other class of fugitive channels consists of epithelial cell Na+ channels. Epithelial cells in the kidney, intestine, skin and secretory glands contain a voltage-independent Na+ channel on their apical (lumenal) surface [2]. Trans- port of Naf ions through these epithelial Na+ channels is the rate-limiting step of