Pervanadate inhibits volume-sensitive chloride current in bovine chromaffin cells

Pflugers Arch. 1998 Jan;435(2):303-9. doi: 10.1007/s004240050516.

Abstract

The role of protein tyrosine phosphorylation in the activation of the volume-sensitive Cl- current in bovine chromaffin cells was investigated by studying the effects of inhibitors of protein tyrosine kinases (PTKs) and phosphatases (PTPs). The whole-cell current was induced by intracellular guanosine-5'-0-(3-thiotriphosphate) (GTP-[gamma-S], 100-250 microM), the nonhydrolysable GTP analogue, or by cell inflation through the patch pipette under voltage-clamp conditions. PTK inhibitors tyrphostin B46 (5-50 microM) and genistein (200 microM) did not inhibit the volume-sensitive Cl- current nor did they induce it in the absence of other stimuli. In contrast, the PTP inhibitor pervanadate (200 microM) applied intracellularly prevented activation of the current. Voltage-activated Na+ and Ca2+ currents were unaffected by pervanadate. Neither sodium orthovanadate nor hydrogen peroxide alone mimicked the action of pervanadate. Other PTP inhibitors tested, i.e. ammonium molybdate (10-100 microM), phenylarsine oxide (10 microM), and ZnCl2 (500 microM), as well as the serine/threonine protein phosphatases inhibitor okadaic acid (200 nM) failed to inhibit the volume-sensitive Cl- current. It is suggested that the inhibitory action of pervanadate indicates the involvement of protein tyrosine phosphorylation in the regulation of volume-sensitive Cl- channels in bovine chromaffin cells. The possibility of pervanadate acting via a pathway unrelated to protein phosphorylation is also discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzylidene Compounds / pharmacology
  • Cattle
  • Cells, Cultured
  • Chloride Channels / drug effects*
  • Chloride Channels / physiology*
  • Chromaffin System / physiology*
  • Electric Conductivity
  • Enzyme Inhibitors / pharmacology*
  • Genistein / pharmacology
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Nitriles / pharmacology
  • Protein Tyrosine Phosphatases / antagonists & inhibitors*
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Tyrphostins*
  • Vanadates / pharmacology*

Substances

  • Benzylidene Compounds
  • Chloride Channels
  • Enzyme Inhibitors
  • Nitriles
  • Tyrphostins
  • alpha-cyano-(3,4-dihydroxy)-N-(3-phenylpropyl)cinnamide
  • pervanadate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Vanadates
  • Genistein
  • Protein-Tyrosine Kinases
  • Protein Tyrosine Phosphatases