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NAADP-sensitive Ca2+ stores in permeabilized rat hepatocytes
Ukrainian Biochemical Journal
|March 31, 2015
Summary
Nicotinic acid adenine dinucleotide phosphate (NAADP) releases calcium from intracellular stores. This study investigates NAADP
Area of Science:
- Cellular Biology
- Biochemistry
- Physiology
Background:
- Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent calcium-releasing nucleotide.
- NAADP primarily targets the endolysosomal system, but its effect on the endoplasmic reticulum (ER) remains unclear.
Purpose of the Study:
- To investigate the NAADP-sensitive calcium stores in permeabilized rat hepatocytes.
- To elucidate the role of the ER in NAADP-mediated calcium release.
Main Methods:
- Monitoring intracellular Ca2+ levels using chlorotetracycline (CTC) in permeabilized rat hepatocytes.
- Assessing NAADP's effect under varying EGTA-Ca2+-buffer concentrations and in the presence of ryanodine.
- Testing sensitivity to nigericin, bafilomycin A, thapsigargin, and the NAADP antagonist NED-19.
Main Results:
- NAADP-induced Ca2+ changes in hepatocytes were dependent on EGTA-Ca2+-buffer concentration.
- The effect of NAADP was enhanced by ryanodine pretreatment, suggesting ER luminal calcium involvement.
- NAADP-evoked Ca2+ release was sensitive to inhibitors of lysosomal and ER function and abolished by NED-19.
Conclusions:
- NAADP-sensitive calcium stores in rat hepatocytes are influenced by ER luminal calcium.
- NAADP-evoked calcium release involves pathways sensitive to lysosomal and ER function inhibitors.
- NED-19 effectively antagonizes NAADP-mediated calcium release in hepatocytes.
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