Endothelin-1 contributes to normocapnic hyperoxic pial artery vasoconstriction

The present study was designed to determine if hyperoxia elicits pial artery vasoconstriction and to characterize the contribution of endothelin-1 (ET-1) to that vascular response in newborn pigs equipped with a closed cranial window. Hyperoxic conditions were established by ventilating the piglets with 100% O-2 during normocapnia and concomitantly topically applying artificial CSF that had been bubbled with 100% O-2. Hyperoxia elevated CSF ET-1 from 23 +/- 1 to 45 +/- 4 pg/ml. Hyperoxia also elicited pial artery vasoconstriction that was attenuated by BQ123 (10(-6) M), an ET-1 antagonist (-15 +/- 1 vs. -5 +/- 1%). These data indicate that ET-1 contributes to hyperoxic pial artery vasoconstriction. (C) 1999 Elsevier Science B.V. All rights reserved.