Diadenosine Polyphosphates Increase Cytosolic Calcium and Attenuate Angiotensin-ll-lnduced Changes of Calcium in Vascular Smooth Muscle Cells

1996 ◽  
Vol 33 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Martin Tepel ◽  
Jürgen Bachmann ◽  
Hartmut Schlüter ◽  
Walter Zidek
Planta Medica ◽  
2020 ◽  
Vol 86 (18) ◽  
pp. 1345-1352
Author(s):  
Min Kyung Kim ◽  
A Young Han ◽  
You Kyoung Shin ◽  
Kwang-Won Lee ◽  
Geun Hee Seol

Abstract Codonopsis lanceolata has been widely used as an anti-inflammatory and anti-lipogenic agent in traditional medicine. Recently, C. lanceolata was reported to prevent hypertension by improving vascular function. This study evaluated the effects of C. lanceolata and its major component lancemaside A on cytosolic calcium concentration in vascular endothelial cells and vascular smooth muscle cells. Cytosolic calcium concentration was measured using fura-2 AM fluorescence. C. lanceolata or lancemaside A increased the cytosolic calcium concentration by releasing Ca2+ from the endoplasmic reticulum and sarcoplasmic reticulum and by Ca2+ entry into endothelial cells and vascular smooth muscle cells from extracellular sources. The C. lanceolata- and lancemaside A-induced cytosolic calcium concentration increases were significantly inhibited by lanthanum, an inhibitor of non-selective cation channels, in both endothelial cells and vascular smooth muscle cells. Moreover, C. lanceolata and lancemaside A significantly inhibited store-operated Ca2+ entry under pathological extracellular Ca2+ levels. In Ca2+-free extracellular fluid, increases in the cytosolic calcium concentration induced by C. lanceolata or lancemaside A were significantly inhibited by U73122, an inhibitor of phospholipase C, and 2-APB, an inositol 1,4,5-trisphosphate receptor antagonist. In addition, dantrolene treatment, which inhibits Ca2+ release through ryanodine receptor channels, also inhibited C. lanceolata- or lancemaside A-induced increases in the cytosolic calcium concentration through the phospholipase C/inositol 1,4,5-trisphosphate pathway. These results suggest that C. lanceolata and lancemaside A increase the cytosolic calcium concentration through the non-selective cation channels and phospholipase C/inositol 1,4,5-trisphosphate pathways under physiological conditions and inhibit store-operated Ca2+ entry under pathological conditions in endothelial cells and vascular smooth muscle cells. C. lanceolata or lancemaside A can protect endothelial cells and vascular smooth muscle cells by maintaining cytosolic calcium concentration homeostasis, suggesting possible applications for these materials in diets for preventing vascular damage.


1991 ◽  
Vol 261 (5) ◽  
pp. C845-C856 ◽  
Author(s):  
D. C. Batlle ◽  
M. Godinich ◽  
M. S. LaPointe ◽  
E. Munoz ◽  
F. Carone ◽  
...  

This study examined contribution of Na(+)-dependent processes to the regulation of free cytosolic calcium (Ca2+i) in cultured vascular smooth muscle cells (VSMC) using fura-2. Removal of Na+ from superfusate (replacement with choline) resulted in an increment of Ca2+i that was greatly augmented by pretreatment with ouabain. Under both conditions, Ca2+i increase was followed by partial recovery to a new steady state that was still significantly higher than that seen before removal of external Na+ (Na+o). In ouabain-pretreated cells lowering of Na+o caused progressive increases in Ca2+i. Addition of NiCl2, a Na(+)-Ca2+ exchange inhibitor, completely blocked the increase in Ca2+i produced by removal of Na+o, indicating that the Na(+)-Ca2+ antiporter was responsible for observed Ca2+i changes. Ca2+i increase produced by reduction of Na+o was also seen after depletion of inositol trisphosphate-sensitive Ca2+ stores with repeated pulses of angiotensin II or after blockade of sarcoplasmatic reticulum Ca2+ release with TMB-8 but was not observed in the absence of external Ca2+. These observations indicate that the source of Ca2+i increase in response to changes in the transmembrane Na+ gradient is largely external, and potentiation of the Ca2+i surge by ouabain suggests Ca2+ influx via the Na(+)-Ca2+ exchanger operating in the reverse mode. The relative contribution of a Na(+)-dependent and -independent component of Ca2+i recovery was investigated by superfusing cells with ionomycin in a Na(+)-free medium and later adding Na+ to the medium. This Ca2+ ionophore increased Ca2+i to a peak, and this was followed by a rapid but partial recovery to a new steady state. Readdition of varying amounts of Na+ to the superfusate, in the continued presence of ionomycin, resulted in concentration-related decline in Ca2+i, thereby uncovering a substantial contribution of a Na(+)-dependent mechanism of Ca2+i regulation. Decline of Ca2+i produced by readdition of Na+ was blocked by addition of NiCl2 to the superfusate. Our findings thereby provide evidence for Ca2+i regulation in VSMC via a Na(+)-dependent mechanism, consistent with a Na(+)-Ca2+ exchanger, which acts as a Ca2+ efflux mechanism when Ca2+i is elevated. Na(+)-Ca2+ exchanger acts as a Ca2+ influx mechanism when intracellular Na+ is elevated by prior exposure to ouabain.


Sign in / Sign up

Export Citation Format

Share Document