Bretylium-induced voltage-gated sodium current in human lymphocytes

Rezsõ Gáspár, Zoltán Krasznai, Teréz Márián, Lajos Trón, Rina Recchioni, Marco Falasca, Fausto Moroni, Carlo Pieri, Sándor Damjanovich

Research output: Contribution to journalArticle

15 Citations (Scopus)

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 languageEnglish
Pages (from-to)143-147
Number of pages5
JournalBBA - Molecular Cell Research
Volume1137
Issue number2
DOIs
Publication statusPublished - Oct 27 1992

Keywords

  • (Human lymphocyte)
  • Bretylium
  • Ion channel
  • Patch-clamp

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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