Endothelin ETA and ETB receptors in subarachnoid hemorrhage-induced cerebral vasospasm.

The relative roles of endothelin ETA and ETB receptor activation in cerebral vasospasm following subarachnoid hemorrhage were investigated in the rabbit. The endothelin ETA receptor antagonist, BQ610 (1 microM; homopiperidinyl-CO-Leu-D-Trp(CHO)-D-Trp-OH), and the endothelin ETA/ETB receptor antagonist, PD145065 (1 microM; Ac-D-Bhg-L-Leu-L-Asp-L-Ile-L-Ile-L-Trp), relaxed the vasospastic basilar artery in situ by 45% and 87%, respectively. These results suggest that subarachnoid hemorrhage-induced vasospasm of the rabbit basilar artery is due to activation of both endothelin ETA and ETB receptors.