Blockage of chloride channels by HEPES buffer.

Chloride channels of neurons of Drosophila are blocked when the cytoplasmic side of the membrane is exposed to the commonly used buffering agents 4-(2-hydroxyethyl)-1-piperazine ethanesulphonic acid (HEPES) and 4-morpholinepropanesulphonic acid (MOPS). In the presence of these compounds, chloride channels appear to function as a complex of multiple protochannels.