Effect of Sphingosine-1-Phosphate on Intracellular Free Ca2+ in Cat Esophageal Smooth Muscle Cells.
10.4062/biomolther.2018.053
- Author:
Dong Kyu LEE
1
;
Young Sil MIN
;
Seong Su YOO
;
Hyun Sub SHIM
;
Sun Young PARK
;
Uy Dong SOHN
Author Information
1. Department of Pharmacology, College of Pharmacy, Chung-Ang University, Seoul 06911, Republic of Korea. udsohn@cau.ac.kr
- Publication Type:Original Article
- Keywords:
Sphingosine-1-phosphate;
Calcium;
Fura-2;
Esophageal cells;
2-Aminoethoxydiphenyl borate;
Nimodipine
- MeSH:
Animals;
Calcium;
Cats*;
Egtazic Acid;
Fura-2;
Methods;
Microscopy, Fluorescence;
Muscle Contraction;
Muscle, Smooth*;
Myocytes, Smooth Muscle*;
Nimodipine;
Pertussis Toxin;
Phospholipases;
Sarcoplasmic Reticulum;
Thapsigargin;
Type C Phospholipases
- From:Biomolecules & Therapeutics
2018;26(6):546-552
- CountryRepublic of Korea
- Language:English
-
Abstract:
A comprehensive collection of proteins senses local changes in intracellular Ca²⁺ concentrations ([Ca²⁺](i) and transduces these signals into responses to agonists. In the present study, we examined the effect of sphingosine-1-phosphate (S1P) on modulation of intracellular Ca²⁺ concentrations in cat esophageal smooth muscle cells. To measure [Ca²⁺](i) levels in cat esophageal smooth muscle cells, we used a fluorescence microscopy with the Fura-2 loading method. S1P produced a concentration-dependent increase in [Ca²⁺](i) in the cells. Pretreatment with EGTA, an extracellular Ca²⁺ chelator, decreased the S1P-induced increase in [Ca²⁺](i), and an L-type Ca²⁺-channel blocker, nimodipine, decreased the effect of S1P. This indicates that Ca²⁺ influx may be required for muscle contraction by S1P. When stimulated with thapsigargin, an intracellular calcium chelator, or 2-Aminoethoxydiphenyl borate (2-APB), an InsP₃ receptor blocker, the S1P-evoked increase in [Ca²⁺](i) was significantly decreased. Treatment with pertussis toxin (PTX), an inhibitor of G(i)-protein, suppressed the increase in [Ca²⁺](i) evoked by S1P. These results suggest that the S1P-induced increase in [Ca²⁺](i) in cat esophageal smooth muscle cells occurs upon the activation of phospholipase C and subsequent release of Ca²⁺ from the InsP₃-sensitive Ca²⁺ pool in the sarcoplasmic reticulum. These results suggest that S1P utilized extracellular Ca²⁺ via the L type Ca²⁺ channel, which was dependent on activation of the S1P₄ receptor coupled to PTX-sensitive G(i) protein, via phospholipase C-mediated Ca²⁺ release from the InsP₃-sensitive Ca²⁺ pool in cat esophageal smooth muscle cells.
