Inositol 1,4,5-trisphosphate and cyclic ADP-ribose mobilize Ca2+ in a protist, Euglena gracilis

Comp Biochem Physiol C Pharmacol Toxicol Endocrinol. 1997 Nov;118(3):279-83. doi: 10.1016/s0742-8413(97)00173-4.

Abstract

Inositol 1,4,5-trisphosphate (InsP3) and cyclic ADP-ribose (cADPR) released Ca2+ from microsome fraction prepared from Euglena gracilis in dose-dependent manners. Caffeine, which also induced Ca2+ release from the microsomes, caused desensitization of the Ca2+ response to cADPR, although the Ca2+ response to InsP3 was not affected by caffeine. Further, ruthenium red inhibited the Ca2+ release induced by cADPR, but not by InsP3. These results suggest that cADPR functions as an endogenous messenger to activate a caffeine-sensitive, Ca(2+)-release mechanism, whereas InsP3 induces Ca2+ release by a distinct mechanism in E. gracilis.

MeSH terms

  • Adenosine Diphosphate Ribose / analogs & derivatives*
  • Adenosine Diphosphate Ribose / antagonists & inhibitors
  • Adenosine Diphosphate Ribose / pharmacology
  • Animals
  • Caffeine / pharmacology
  • Calcium / metabolism*
  • Cell Cycle / drug effects
  • Cyclic ADP-Ribose
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Euglena gracilis
  • Inositol 1,4,5-Trisphosphate / pharmacology*
  • Microsomes / drug effects
  • Microsomes / metabolism
  • Phosphodiesterase Inhibitors / pharmacology
  • Ruthenium Red / pharmacology

Substances

  • Phosphodiesterase Inhibitors
  • Ruthenium Red
  • Cyclic ADP-Ribose
  • Adenosine Diphosphate Ribose
  • Caffeine
  • Inositol 1,4,5-Trisphosphate
  • Calcium