Effects of SH-group reagents on Ca2+ and K+ channel currents of pancreatic B-cells

Biochem Biophys Res Commun. 1994 Apr 29;200(2):860-6. doi: 10.1006/bbrc.1994.1530.

Abstract

The whole-cell patch-clamp technique has been applied to elucidate the effects of H2O2 and the SH-group reagent 2,2'-dithio-bis(5-nitropyridine) (DTBNP) on Ca2+ currents of mouse pancreatic B-cells. We also tested the effect of DTBNP on the whole-cell K+ ATP current. DTBNP (20 and 100 mumol/l) blocked both the current through Ca2+ channels (with Ba2+ as the charge carrier) and the K+ATP current in a concentration-dependent manner. The results suggest that the channels themselves or regulating proteins possess free SH-groups which may be of functional relevance. However, H2O2 did not influence the Ca2+ channel currents under standard whole-cell conditions as well as when recorded with the perforated patch technique. These results indicate that the two agents act differently on ion channel currents in B-cells although both are known to oxidize SH-groups.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Calcium Channels / drug effects*
  • Calcium Channels / metabolism
  • Female
  • Hydrogen Peroxide / pharmacology
  • In Vitro Techniques
  • Islets of Langerhans / drug effects*
  • Islets of Langerhans / metabolism*
  • Membrane Potentials
  • Mice
  • Potassium Channels / drug effects
  • Potassium Channels / metabolism
  • Pyridines / pharmacology*
  • Sulfhydryl Reagents / pharmacology*

Substances

  • Calcium Channels
  • Potassium Channels
  • Pyridines
  • Sulfhydryl Reagents
  • 2,2'-dithiobis(5-nitropyridine)
  • Adenosine Triphosphate
  • Hydrogen Peroxide