148 Binding of tPA to human vascular smooth muscle cells alters the kinetics of its inactivation by both low molecular weight and macromolecular inhibitors

1997 ◽  
Vol 11 ◽  
pp. 42
Author(s):  
Finn Werner ◽  
Vincent Ellis
1995 ◽  
Vol 268 (1) ◽  
pp. C14-C20 ◽  
Author(s):  
G. Hoffmann ◽  
Y. Ko ◽  
A. Sachinidis ◽  
B. O. Gobel ◽  
H. Vetter ◽  
...  

The kinetic properties of Na+/H+ exchange were investigated in vascular smooth muscle cells (VSMC) in culture from normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Antiport activity was measured in 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein-loaded cells after nigericin-induced cytosolic acidification. Studies were performed without (control) and with pretreatment of the cells with phorbol 12-myristate 13-acetate (PMA; 200 nM). Na+/H+ exchange markedly differed between the two strains with lower Hill coefficients [1.56 +/- 0.17 (SE) vs. 2.62 +/- 0.36] and higher maximal activity (Vmax) values (55.85 +/- 5.24 vs. 31.11 +/- 2.38 mmol H+.l-1.min-1) in SHR compared with WKY cell lines. PMA markedly altered the antiport kinetics in WKY VSMC with a decrease in the Hill coefficient (1.75 +/- 0.14) without affecting Vmax (31.88 +/- 1.55 mmol H+.l-1.min-1). In VSMC from SHR, PMA had no effect on the kinetic variables investigated. Thus two kinetic abnormalities are present with respect to Na+/H+ antiport activity in VSMC from SHR compared with WKY, i.e., increased Vmax and decreased Hill coefficient. The observation that PMA does not affect the kinetics of the Na+/H+ antiport in VSMC from SHR suggests a marked degree of antiporter prestimulation in this animal model of genetic hypertension.


2007 ◽  
Vol 19 (5) ◽  
pp. 1023-1033 ◽  
Author(s):  
Sharon M. Cawley ◽  
Carolyn L. Sawyer ◽  
Kara F. Brunelle ◽  
Albert van der Vliet ◽  
Wolfgang R. Dostmann

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