Mn2+ activates skinned smooth muscle cells in the absence of myosin light chain phosphorylation

1988 ◽  
Vol 412 (3) ◽  
pp. 225-230 ◽  
Author(s):  
Phyllis E. Hoar ◽  
W. Glenn L. Kerrick
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Cells ◽  
Myosin Light Chain Phosphorylation ◽  
Skinned Smooth Muscle

scholarly journals Apelin Stimulates Myosin Light Chain Phosphorylation in Vascular Smooth Muscle Cells

2006 ◽  
Vol 26 (6) ◽  
pp. 1267-1272 ◽  
Author(s):  
Tatsuo Hashimoto ◽  
Minoru Kihara ◽  
Junji Ishida ◽  
Nozomi Imai ◽  
Shin-ichiro Yoshida ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Cells ◽  
Myosin Light Chain Phosphorylation

Myosin light chain phosphorylation in human myometrial smooth muscle cells

1990 ◽  
Vol 258 (1) ◽  
pp. C92-C98 ◽  
Author(s):  
L. W. Mackenzie ◽  
R. A. Word ◽  
M. L. Casey ◽  
J. T. Stull
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Cells ◽  
Myosin Light Chain Phosphorylation ◽  
Myometrial Cells ◽  
Muscle Tissues ◽  
Primary Determinant ◽  
The Relationship

Ca2+/calmodulin-dependent phosphorylation of the 20-kDa regulatory light chain of myosin is of signal importance in the initiation of contraction in a number of smooth muscle tissues. In this investigation, we evaluated the relationship between intracellular free Ca2+/concentration [( Ca2+]i) and the extent of myosin light chain phosphorylation in cultured human myometrial smooth muscle cells. Treatment of myometrial cells with ionomycin caused a concentration- and time-dependent increase in [Ca2+]i and phosphorylation of myosin light chain. Temporally, the increases in light chain phosphorylation and [Ca2+]i in response to ionomycin were similar. In myometrial cells treated with ionomycin (10(-5) M) for 10 s, [Ca2+]i increased from 138 to 800 nM; in these same cells, myosin light chain phosphorylation increased from 5% to a maximum value of 54%. Half-maximal phosphorylation of myosin light chain was attained at 300 nM [Ca2+]i. Treatment of myometrial smooth muscle cells with prostaglandin (PG) F2 alpha (10(-8) M) and PGE2 (10(-8) M) caused a proportionate increase in [Ca2+]i and myosin light chain phosphorylation. In addition, [Ca2+]i and myosin light chain phosphorylation increased in response to oxytocin and angiotensin II. These findings indicate that a number of uterotonic agents effect an increase in [Ca2+]i, which in turn causes phosphorylation of myosin light chain. Furthermore, the concentration of Ca2+ in the cytoplasm is a primary determinant for myosin light chain phosphorylation in human myometrial smooth muscle cells.

scholarly journals Rapid effects of aldosterone on clonal human vascular smooth muscle cells

2007 ◽  
Vol 292 (2) ◽  
pp. C788-C794 ◽  
Author(s):  
Robert Gros ◽  
Qingming Ding ◽  
Souzan Armstrong ◽  
Caroline O'Neil ◽  
J. Geoffrey Pickering ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Cells ◽  
Myosin Light Chain Phosphorylation ◽  
Phosphatidylinositol 3 Kinase ◽  
Dose Dependent

It has been increasingly appreciated that aldosterone elicits acute vascular effects through nongenomic signaling pathways. Our previous studies demonstrated that aldosterone attenuated phenylephrine-mediated constriction in intact vessels [via phosphatidylinositol 3-kinase-dependent nitric oxide synthase activation] but enhanced vasoconstrictor responses in endothelium-denuded arteries. To determine the mechanism of this vasoconstrictor response, we assessed the effect of aldosterone on myosin light-chain phosphorylation and contraction in clonal adult human vascular smooth muscle cells. Acute aldosterone exposure mediated dose-dependent myosin light-chain phosphorylation, inhibited by spironolactone and phosphatidylinositol 3-kinase inhibition. These rapid effects of aldosterone were mimicked by estradiol and hydrocortisone and were also inhibitable by both spironolactone and eplerenone. In parallel to its effects on myosin light-chain phosphorylation, aldosterone mediated dose-dependent contraction responses that were inhibited by spironolactone. Comparable contractile responses were seen with both 17β-estradiol and hydrocortisone. In total, these data are consistent with a mechanism of acute aldosterone-mediated contraction common to both glucocorticoids and estrogen. Steroid-mediated vasoconstriction may represent an important pathobiological mechanism of vascular disease, especially in the setting of preexisting endothelial dysfunction.

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