Abstract
Using the whole-cell variation of the patch-clamp technique it has been determined that 0.25-3 mM bretylium tosylate (BT) exerts a repolarizing effect on partially depolarized human lymphocytes. The repolarizing effect was ouabain (40 μM)-sensitive, and was inhibited by the removal of external Na+ or by the Na+-channel-blocker amiloride (10-44 μM), but K+-channel-blockers 4-aminopyridine (0.1-5 mM) and quinine (100 μM) had no effect. The drug induced a sodium dependent, amiloride-sensitive transient inward current reaching its maximum value approx. 20-30 s after the administration of BT and lasting for 6-10 min. This current was activated by depolarization within 25 ms at around -42 mV, its inactivation took about 2 s and its reversal potential was +24±5 mV. An increase in the intracellular sodium concentration (1.8-3.2 mM) has been observed upon the addition of BT by monitoring the SBFI fluorescence of the dye-loaded cells. It has been shown that whole-cell K+ currents are significantly decreased by BT. The existence of voltage and ligand (BT)-gated sodium channels has been postulated in human lymphocytes. These channels are thought to participate in the initiation of membrane repolarization in human lymphocytes, and thereby influence mitogenic or antigen-induced cell-activation processes.
| Original language | English |
|---|---|
| Pages (from-to) | 143-147 |
| Number of pages | 5 |
| Journal | Biochimica et Biophysica Acta - Molecular Cell Research |
| Volume | 1137 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Oct 27 1992 |
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Keywords
- (Human lymphocyte)
- Bretylium
- Ion channel
- Patch-clamp
ASJC Scopus subject areas
- Biophysics
- Cell Biology
- Molecular Biology
Cite this
Bretylium-induced voltage-gated sodium current in human lymphocytes. / Gáspár, Rezsõ; Krasznai, Zoltán; Márián, Teréz; Trón, Lajos; Recchioni, Rina; Falasca, Marco; Moroni, Fausto; Pieri, Carlo; Damjanovich, Sándor.
In: Biochimica et Biophysica Acta - Molecular Cell Research, Vol. 1137, No. 2, 27.10.1992, p. 143-147.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Bretylium-induced voltage-gated sodium current in human lymphocytes
AU - Gáspár, Rezsõ
AU - Krasznai, Zoltán
AU - Márián, Teréz
AU - Trón, Lajos
AU - Recchioni, Rina
AU - Falasca, Marco
AU - Moroni, Fausto
AU - Pieri, Carlo
AU - Damjanovich, Sándor
PY - 1992/10/27
Y1 - 1992/10/27
N2 - Using the whole-cell variation of the patch-clamp technique it has been determined that 0.25-3 mM bretylium tosylate (BT) exerts a repolarizing effect on partially depolarized human lymphocytes. The repolarizing effect was ouabain (40 μM)-sensitive, and was inhibited by the removal of external Na+ or by the Na+-channel-blocker amiloride (10-44 μM), but K+-channel-blockers 4-aminopyridine (0.1-5 mM) and quinine (100 μM) had no effect. The drug induced a sodium dependent, amiloride-sensitive transient inward current reaching its maximum value approx. 20-30 s after the administration of BT and lasting for 6-10 min. This current was activated by depolarization within 25 ms at around -42 mV, its inactivation took about 2 s and its reversal potential was +24±5 mV. An increase in the intracellular sodium concentration (1.8-3.2 mM) has been observed upon the addition of BT by monitoring the SBFI fluorescence of the dye-loaded cells. It has been shown that whole-cell K+ currents are significantly decreased by BT. The existence of voltage and ligand (BT)-gated sodium channels has been postulated in human lymphocytes. These channels are thought to participate in the initiation of membrane repolarization in human lymphocytes, and thereby influence mitogenic or antigen-induced cell-activation processes.
AB - Using the whole-cell variation of the patch-clamp technique it has been determined that 0.25-3 mM bretylium tosylate (BT) exerts a repolarizing effect on partially depolarized human lymphocytes. The repolarizing effect was ouabain (40 μM)-sensitive, and was inhibited by the removal of external Na+ or by the Na+-channel-blocker amiloride (10-44 μM), but K+-channel-blockers 4-aminopyridine (0.1-5 mM) and quinine (100 μM) had no effect. The drug induced a sodium dependent, amiloride-sensitive transient inward current reaching its maximum value approx. 20-30 s after the administration of BT and lasting for 6-10 min. This current was activated by depolarization within 25 ms at around -42 mV, its inactivation took about 2 s and its reversal potential was +24±5 mV. An increase in the intracellular sodium concentration (1.8-3.2 mM) has been observed upon the addition of BT by monitoring the SBFI fluorescence of the dye-loaded cells. It has been shown that whole-cell K+ currents are significantly decreased by BT. The existence of voltage and ligand (BT)-gated sodium channels has been postulated in human lymphocytes. These channels are thought to participate in the initiation of membrane repolarization in human lymphocytes, and thereby influence mitogenic or antigen-induced cell-activation processes.
KW - (Human lymphocyte)
KW - Bretylium
KW - Ion channel
KW - Patch-clamp
UR - http://www.scopus.com/inward/record.url?scp=0026768613&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026768613&partnerID=8YFLogxK
U2 - 10.1016/0167-4889(92)90195-H
DO - 10.1016/0167-4889(92)90195-H
M3 - Article
C2 - 1329976
AN - SCOPUS:0026768613
VL - 1137
SP - 143
EP - 147
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
SN - 0167-4889
IS - 2
ER -