FIGURE 6.

FXa enzymatic activity in homogenates of mesentery from saline-injected rats (A) and from heparin-injected rats (B). The mesentery, including mesenteric artery and its branches, was removed from rats injected with saline or 5,000 U/kg low molecular weight heparin 1 h before sacrifice, homogenized and incubated with the chromogenic substrate Biophen CS-11, with or without apixaban (APX, 1 or 10 μM). Notice that in homogenate from control rat apixaban inhibits in an apparent competitive manner the enzymatic activity, whereas in homogenate from heparin-treated rat the enzymatic activity is decreased and barely sensitive to apixaban. Data are reported after appropriate subtraction of background; each concentration point was run in triplicate; the experiment has been repeated twice with similar results.