Activation of a Cl(-)-conductive pathway in primary cultures of rat inner medullary collecting duct (IMCD) cells under hypotonic stress.

In intracellular recordings with conventional microelectrodes on rat IMCD cells, we find that hypotonic stress depolarizes membrane voltage and decreases cell input resistance. Ion substitution experiments reveal that these effects are largely due to the activation of a prominent Cl- conductance. After block of this conductance with dideoxyforskolin a smaller concomitant increase in K+ conductance becomes detectable.