Figure 1.

Concentration-effect curves for the vasoconstriction of rings of basilar artery elicited by endothelin-1 (0.5 nM) in the absence or presence of a selective antagonist of ET_A receptor, BQ-123 (0.1 μM). Values are expressed as a percentage (% control) of the response observed in the absence of the antagonist. Data points represent means±s.e.mean (bars) for measurements with four to five individual ring preparations.