These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Na+-H+ exchange activity in taste receptor cells.
    Author: Vinnikova AK, Alam RI, Malik SA, Ereso GL, Feldman GM, McCarty JM, Knepper MA, Heck GL, DeSimone JA, Lyall V.
    Journal: J Neurophysiol; 2004 Mar; 91(3):1297-313. PubMed ID: 14602837.
    Abstract:
    mRNA for two Na(+)-H(+)-exchanger isoforms 1 and 3 (NHE-1 and NHE-3) was detected by RT-PCR in fungiform and circumvallate taste receptor cells (TRCs). Anti-NHE-1 antibody binding was localized to the basolateral membranes, and the anti-NHE-3 antibody was localized in the apical membranes of fungiform and circumvallate TRCs. In a subset of TRCs, NHE-3 immunoreactivity was also detected in the intracellular compartment. For functional studies, an isolated lingual epithelium containing a single fungiform papilla was mounted with apical and basolateral sides isolated and perfused with nominally CO(2)/HCO(3)(-)-free physiological media (pH 7.4). The TRCs were monitored for changes in intracellular pH (pH(i)) and Na(+) ([Na(+)](i)) using fluorescence ratio imaging. At constant external pH, 1) removal of basolateral Na(+) reversibly decreased pH(i) and [Na(+)](i); 2) HOE642, a specific blocker, and amiloride, a nonspecific blocker of basolateral NHE-1, attenuated the decrease in pH(i) and [Na(+)](i); 3) exposure of TRCs to basolateral NH(4)Cl or sodium acetate pulses induced transient decreases in pH(i) that recovered spontaneously to baseline; 4) pH(i) recovery was inhibited by basolateral amiloride, 5-(N-methyl-N-isobutyl)-amiloride (MIA), 5-(N-ethyl-N-isopropyl)-amiloride (EIPA), HOE642, and by Na(+) removal; 5) HOE642, MIA, EIPA, and amiloride inhibited pH(i) recovery with K(i) values of 0.23, 0.46, 0.84, and 29 microM, respectively; and 6) a decrease in apical or basolateral pH acidified TRC pH(i) and inhibited spontaneous pH(i) recovery. The results indicate the presence of a functional NHE-1 in the basolateral membranes of TRCs. We hypothesize that NHE-1 is involved in sour taste transduction since its activity is modulated during acid stimulation.
    [Abstract] [Full Text] [Related] [New Search]