Ca2+ release from isolated sarcoplasmic reticulum of guinea-pig psoas muscle induced by K(+)-channel blockers

Br J Pharmacol. 1992 Aug;106(4):764-5. doi: 10.1111/j.1476-5381.1992.tb14409.x.

Abstract

A Ca(2+)-sensitive electrode was used to measure the Ca2+ concentration of the medium containing the heavy fraction of the fragmented sarcoplasmic reticulum (SR) prepared from guinea-pig psoas muscle. Among K(+)-channel blockers tested, 4-aminopyridine (4-AP), tetraethylammonium (TEA) and charybdotoxin elicited Ca2+ release from the SR, but apamin and glibenclamide did not. These results suggest that a reduction of SR K+ conductance leads to Ca2+ release from the SR.

MeSH terms

  • 4-Aminopyridine / pharmacology
  • Animals
  • Apamin / pharmacology
  • Calcium / metabolism*
  • Charybdotoxin
  • Glyburide / pharmacology
  • Guinea Pigs
  • In Vitro Techniques
  • Muscle Contraction / drug effects*
  • Potassium Channels / drug effects*
  • Psoas Muscles / drug effects
  • Sarcoplasmic Reticulum / metabolism*
  • Scorpion Venoms / pharmacology
  • Tetraethylammonium
  • Tetraethylammonium Compounds / pharmacology

Substances

  • Potassium Channels
  • Scorpion Venoms
  • Tetraethylammonium Compounds
  • Charybdotoxin
  • Apamin
  • Tetraethylammonium
  • 4-Aminopyridine
  • Glyburide
  • Calcium