Cl- channels in intact human T lymphocytes. J Membr Biol 1992 Jan;125(2):171-83
Date
01/01/1992Pubmed ID
1372657DOI
10.1007/BF00233356Scopus ID
2-s2.0-0026541634 (requires institutional sign-in at Scopus site) 56 CitationsAbstract
We recently described a large, multiple-conductance Cl- channel in excised patches from normal T lymphocytes. The properties of this channel in excised patches are similar to maxi-Cl- channels found in a number of cell types. The voltage dependence in excised patches permitted opening only at nonphysiological voltages, and channel activity was rarely seen in cell-attached patches. In the present study, we show that Cl- channels can be activated in intact cells at physiological temperatures and voltages and that channel properties change after patch excision. Maxi-Cl- channels were reversibly activated in 69% of cell-attached patches when the temperature was above 32 degrees C, whereas fewer than 2% of patches showed activity at room temperature. Upon excision, the same patches displayed large, multiple-conductance Cl- channels with characteristics like those we previously reported for excised patches. After patch excision, warm temperatures were not essential to allow channel activity; 37% (114/308) of inside-out patches had active channels at room temperature. The voltage dependence of the channels was markedly different in cell-attached recordings compared with excised patches. In cell-attached patches, Cl- channels could be open at cell resting potentials in the normal range. Channel activation was not related to changes in intracellular Ca2+ since neither ionomycin nor mitogens activated the channels in cell-attached patches, Ca2+ did not rise in response to warming and the Cl- channel was independent of Ca2+ in inside-out patches. Single-channel currents were blocked by internal or external Zn2+ (100-200 microM), 4-acetamido-4' isothiocyanostilbene-2,2'-disulfonate (SITS, 100-500 microM) and 4,4'-diisothiocyanostilbene 2,2'-disulfonate (DIDS, 100 microM). NPPB (5-nitro-2-(3-phenylpropylamino)-benzoate) reversibly blocked the channels in inside-out patches.
Author List
Pahapill PA, Schlichter LCAuthor
Peter A. Pahapill MD, PhD Professor in the Neurosurgery department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
Calcium
Chloride Channels
Chlorides
Electric Conductivity
Humans
Ion Channels
Ionomycin
Membrane Potentials
Membrane Proteins
Nitrobenzoates
T-Lymphocytes
Zinc
Zinc Compounds
