ISSN:
1440-1681
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
1. Previous studies demonstrate that volume-sensitive chloride currents are distinctly activated in cervical cancer cells, but not in human papillomavirus (HPV)-immortalized and normal cervical cells. In the present study, the Na+-independent volume-activated transport of taurine in three cervical cell types was investigated.2. Osmotic swelling of cervical cancer HT-3 cells suspended i. Na+-free hypotonic medium led to increased membrane uptake of taurine. This taurine uptake was effectively blocked by various C1- channel blockers with a similar potency in blocking volume-sensitive C1- channels: l,9-dideoxyforskolin 〉 5-nitro-2-(3-phenyl-propylamino)-benzoic acid (NPPB) 〉 4-acetamido-4′-isothiocyanastilbene-2,2′-disulphonic acid (SITS) 〉 4,4′-diisothio-cyanatostilbene-2,2-disulphonic acid (DIDS)〉furosemide. The taurine influx was also abolished by pertussis toxin. In contrast, Na+-independent volume-activated taurine transport was not significantly activated in HPV-immortalized Z183A cells and in normal cervical cells.3. Exposure of HT-3 cells to hypotonic medium also resulted in a marked increase in taurine efflux. The volume-activated taurine efflux was osmolality dependent and the pattern of pharmacological inhibition by C1- channel blockers was indistinguishable from that for taurine uptake.4. These results suggest that volume-sensitiv. C1- channels in HT-3 cells can mediate the transport of amino acids. In addition, the pertussis toxin-sensitive G-protein is linked with the activation of this transport mechanism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1440-1681.1997.tb02722.x
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