Effect of norepinephrine and angiotensin II on intrarenal oxygen availability

Oxygen availability (O2a) in the cortex, outer medulla, inner medulla, and papilla of the left kidney was measured in 12 unanesthetized rabbits implanted with O2 sensitive electrodes. Each was injected with a single i.v. bolus of either norepinephrine (NE) or angiotensin II (AII) in equipressor doses, and intrarenal O2a was continuously recorded. The NE response consisted of parallel and proportional intrarenal O2a decreases and overshoots in all zones; AII response consisted of progressively smaller O2a decreases from outer to inner zones during maximum response and smaller increases during maximum overshoot. These response differences may be important under various physiologic or pathologic conditions.