Activation of Ca2+ release in isolated sarcoplasmic reticulum

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The relationship between Ca2+ release from sarcoplasmic reticulum, induced by elevated pH, tetraphenylboron (TPB-) or chemical modification, and the change in the surface charge of the membranes as measured by the fluorescence intensity of anilinonaphthalene sulfonate (ANS) is examined. The stimulated Ca2+ release is inhibited by dicyclohexylcarbodiimide and external Ca2+. TPB-, but not tetraphenylarsonium (TPA+), causes a decrease in ANS- fluorescence, with 50% decrease occurring at about 5 μm TPB-. The decrease in ANS- fluorescence as well as the inhibition of Ca2+ accumulation induced by TPB- are prevented by TPA+. A linear relationship between the decrease in membrane surface potential and the extent of the Ca2+ released by TPB- is obtained. Similar levels of [3H]TPB- bound to sarcoplasmic reticulum membranes were obtained regardless of whether or not the vesicles have taken up Ca2+. The inhibition of Ca2+ accumulation and the [3H]TPB- incorporation into the membranes were correlated. Ca2+ release from sarcoplasmic reticulum, by pH elevation, chemical modification or by addition of NaSCN (0.2 to 0.5 m) or the Ca2+ ionophore ionomycin, is also accompanied by a decrease in ANS- fluorescence intensity. However, chemical modification and elevated pH affects the surface potential much less than SCN- or TPB- do. These results suggest that the enhancement of Ca2+ release by these treatments is not due to a general effect on the membrane surface potential, but rather through the modification of a specific protein. They also suggest that membrane surface charges might play an important role in the control mechanism of Ca2+ release.

Original languageEnglish
Pages (from-to)67-77
Number of pages11
JournalJournal of Membrane Biology
Issue number1
StatePublished - 1 Jul 1988


  • ANS fluorescence
  • Ca release
  • sarcoplasmic reticulum
  • surface charge
  • tetraphenylboron

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology


Dive into the research topics of 'Activation of Ca2+ release in isolated sarcoplasmic reticulum'. Together they form a unique fingerprint.

Cite this