Skip Navigation LinksHome > June 1994 - Volume 80 - Issue 6 > Nitric Oxide and Prostanoids Contribute to Isoflurane-induce...

Nitric Oxide and Prostanoids Contribute to Isoflurane-induced Cerebral Hyperemia in Pigs.

Moore, Laurel E. M.D.; Kirsch, Jeffrey R. M.D.; Helfaer, Mark A. M.D.; Tobin, Joseph R. M.D.; McPherson, Robert W. M.D.; Traystman, Richard J. Ph.D.

Collapse Box


Background: The mechanism of isoflurane-induced cerebral hyperemia is poorly understood. Data from studies in vitro suggest that volatile anesthetics release a vasodilator prostanold. We hypothesized that prostanoids and nitric oxide (NO) are mediators of this response in vivo. If true, inhibition of cyclooxygenase by indomethacln (5 mg/kg intravenously) or of nitric oxide synthase by N(R)-nitro-L-arginine methyl ester (L-NAME; 40 mg/kg intravenously) should attenuate isoflurane-induced hyperemia. Any response to L-NAME occurring via nitric oxide should be competitively reversed by L-arginine.
Methods: The cerebral blood flow (microsphere) response to 1 MAC isofiurane was tested at three time points (0, 90, and 180 min) in pentobarbltal-anesthetized pigs. Isofiurane challenges were separated by 60-min periods of continuous intravenous pentobarbital alone. Control animals (n = 7) received no additional pharmacologlc intervention. Experimental animals were randomized to receive L-NAME before the second and indomethacin before the third isofiurane challenge (n = 7); L-NAME before the second and L-arginine (400 mg/kg intravenously) before the third isofiurane challenge (n = 9); or indomethacin before the second and L-NAME before the third isofiurane challenge (n = 8).
Results: In control animals, isofiurane reproducibly increased cerebral blood flow (whole brain; 113 +/- 18%, 120 +/- 18%, and 103 +/- 19% increase above baseline at each time point, respectively). Both indomethacin and L-NAME attenuated (10 +/- 10% and 52 +/- 11% increase, respectively) the hyperemic response to isofiurane. The effect of L-NAME was reversed by L-arginine.
Conclusions: We conclude that both prostanoids and nitric oxide contribute to isoflurane-induced hyperemia. We are unable to determine from our data what, if any, interaction exists between these two mechanisms.
(C) 1994 American Society of Anesthesiologists, Inc.
Publication of an advertisement in Anesthesiology Online does not constitute endorsement by the American Society of Anesthesiologists, Inc. or Lippincott Williams & Wilkins, Inc. of the product or service being advertised.

Article Tools


Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.