Figure 4.

PGE₂-stimulated vasodilatation in human cerebral artery rings in the absence or presence of BGC20-1531. In (A), cerebral artery rings were pre-incubated with BGC20-1531 30 min prior to stimulation with PGE₂, and demonstrated surmountable competitive antagonism. Data are representative of mean ± SEM derived from 4–5 independent experiments at each concentration, and are normalized to the maximal relaxation caused by PGI₂. In (B), Schild analysis of the antagonism of EP₄ receptor mediated PGE₂-stimulated vasodilatation in human middle cerebral artery by increasing concentrations of BGC20-1531 is shown. Data are from 4–5 independent experiments at each concentration and a linear regression slope of unity is shown.