Acidification of the cytosol inhibits the uptake of tetanus toxin in NG108-15 and NBr-10A neurohybridoma cells.

The influence of cytosol acidification on the uptake of two-chain tetanus toxin (TeTX)1 by neurohybridoma cells NG 108-15 and NBr-10A was investigated with two established techniques, the NH4Cl pulse method and the pH-clamp method. With the former, the extracellular pH is maintained at its physiological value, but is set to different values with the latter. Acidification of the cytoplasm with an NH4Cl pulse retarded the uptake of TeTX by both NG 108-15 and NBr-10A cells.