Figure 2.

Mean arterial pressure (MAP) and heart rate (HR) responses to intravenous (iv) injection of clonidine (20 μg/kg) over a 60 min time course following vehicle pretreatment (closed circles) or pretreatment with endothelin–1: 50 ng/kg intravenously (squares), 10 ng/kg intracisternally (ic) (triangle up) or 50 ng/kg intracisternally (triangle down). C1 indicates initial basal values and C2 indicates MAP and heart rate 30 min after pretreatment injection. Error bars are ± 1 SEM from analysis of variance and indicate variation between animals.