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1	Intracellular pH, the Proximate Signal for Cell Volume Changes that are Mediated by the Actin Cytoskeleton Pasley, William 01 January 2005 (has links) The relationship between initial intracellular pH (pHi) and associated cell volume change was investigated by simultaneous measurement of pHi and cell volume with fluorescence imaging in polarized fungiform taste receptor cells (TRCs) loaded with BCECF in vitro. Ammonium pulses caused a brief, reversible alkalinization in pHi and induced cell swelling. Sodium-acetate pulses reversible decreased TRC pHi and induced cell shrinkage. Removal weak acids and return to Control Ringer's solution (CR) causedTRC pHi and volume to overshoot baseline levels before fully recovering. Replacing CR with zero-sodium solution resulted in irreversible acidification of TRC pHi and induced cell swelling. Addition of sodium allowed reversal of TRC pHi and volume and return to baseline levels. Treating TRCs with cytoskeleton inhibitors, phalloidin and cytochalasin, before acidic stimulation did not affect TRC pHi, but did result in an altered TRC volume change. I conclude that a decrease in TRC pHi induces cell shrinkage via the actin cytoskeleton. Cell shrinkage as a result of a change in pHi activates NHE1 to restore TRC pHi and volume. gustation taste receptors actin intracellular cytoskeleton taste papillia pHi TRC taste bud sodium phalloidin cytochalsin Psychology Social and Behavioral Sciences