The Effects of DTBNP on Intracellular Ca2+ Signaling in Cultured Bovine Aortic Endothelial Cells.
- Author:
Sung Jin PARK
1
;
Byung Joo KIM
;
Mei Hong ZHU
;
Insuk SO
;
Ki Whan KIM
Author Information
1. Department of Physiology and Biophysics, Seoul National University College of Medicine, Seoul 110-799, Korea. insuk@plaza.snu.ac.kr
- Publication Type:Original Article
- Keywords:
Oxidant;
DTBNP;
DTT;
Bovine aortic endothelial cells;
Endoplasmic reticulum;
Mitochondria
- MeSH:
Adenosine Triphosphate;
Carbonyl Cyanide m-Chlorophenyl Hydrazone;
Egtazic Acid;
Endoplasmic Reticulum;
Endothelial Cells*;
Fura-2;
Mitochondria;
Thapsigargin
- From:The Korean Journal of Physiology and Pharmacology
2005;9(6):341-346
- CountryRepublic of Korea
- Language:English
-
Abstract:
The mechanism underlying oxidant-induced intracellular Ca2+ ([Ca2+]i) increase was studied in cultured bovine aortic endothelial cells (BAECs) using fura-2 AM. In the presence of 2 mM extracellular Ca2+, the application of DTBNP (20microM), a membrane-permeable oxidant, caused an increase in [Ca2+]i, and DTT (2 mM) as a reductant completely reversed the effect of DTBNP. The [Ca2+]i increase induced by DTBNP was also observed in an extracellular Ca2+-free/2 mM EGTA solution, indicating the release of Ca2+ from intracellular store (s). After endoplasmic reticulum was depleted by an IP3-generating agonist, ATP (30microM) or an ER Ca2+ pump inhibitor, thapsigargin (1microM), DTBNP-stressed BAECs showed an increase of [Ca2+]i in Ca2+-free/2 mM EGTA solution. Ratio-differences before and after the application of DTBNP after pretreatment with ATP or thapsigargin were 0.42+/-0.15 and 0.49+/-0.07, respectively (n=7), which are significantly reduced, compared to the control value of 0.72+/-0.07 in a Ca2+-free/2 mM EGTA solution. After the protonophore CCCP (10microM) challenge to release mitochondrial Ca2+, the similar result was obtained. Ratio-difference before and after the application of DTBNP after pretreatment with CCCP was 0.46+/-0.09 (n=7). Simultaneous application of thapsigargin and CCCP completely abolished the DTBNP-induced [Ca2+]i increase. The above results together indicate that the increase of [Ca2+]i by DTBNP resulted from the release of Ca2+ from both endoplasmic reticulum and mitochondria.
