Potential-induced changes in intracellular pH.
In a variety of cell types and tissues there is a strong dependence of intracellular pH (pHi) on membrane potential (Vm). Since cell Vm values can be altered by hormones, ion concentrations, and changes in membrane conductances, the potential-dependent changes in pHi may serve as an important mechanism by which cells can alter their pHi to an environmental stimulus. The H+ flux across the cell membranes is thought to take place via putative H+ channels that are blocked by low concentrations of divalent metal ions. However, in Na(+)-transporting epithelia, a major part of the H+ flux seems to be via the amiloride-sensitive apical Na+ channels, which are not sensitive to divalent metal ions. The H+ flux via the Na+ channels can be modulated by natriferic hormones and intracellular second messengers. The H(+)-conductive pathways may play an important role in signal transduction in some cells.
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D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002468:Cell Physiological Phenomena; D004848:Epithelium / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials
D007473:Ion Channels