Effects of ryanodine on calcium sequestration in the rat liver

Roberto B. Bazotte, Bethany Pereira, sandra Higham, Varda Shoshan-Barmatzt, Naomi Kraus-Friedmann

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Ryanodine, a highly toxic alkaloid known to react specifically with the Ca2+ release channels in sarcoplasmic reticulum (SR), was employed to study Ca2+ sequestration in the liver. Ryanodine at a 200 μM concentration increased cytosolic free Ca2+ levels and phosphorylase a activity in isolated hepatocytes. These effects may involve microsomal Ca2+ sequestration, because ryanodine, in the presence of inhibitors of mitochondrial Ca2+ uptake, at concentrations of 1 nM, 1 μM, 50 μM and 100 μM decreased 45Ca2+ retention in permeabilized hepatocytes. This inhibition of Ca2+ retention by ryanodine was not due to inhibition of the microsomal Ca2+-ATPase. Dantrolene, a compound shown previously to inhibit ryanodine binding in the liver, also decreased 45Ca2+ retention in permeabilized hepatocytes, and activated phosphorylase a. These results show that ryanodine administration alters calcium sequestration in liver. The possibility of the existence of a ryanodine-sensitive Ca2+-release channel in liver is discussed.

Original languageEnglish
Pages (from-to)1799-1803
Number of pages5
JournalBiochemical Pharmacology
Volume42
Issue number9
DOIs
StatePublished - 9 Oct 1991
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Pharmacology

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