Nitric oxide and prostanoids contribute to isoflurane-induced cerebral hyperemia in pigs

L. E. Moore, J. R. Kirsch, M. A. Helfaer, J. R. Tobin, R. W. McPherson, R. J. Traystman

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32 Scopus citations

Abstract

Background: The mechanism of isoflurane-induced cerebral hyperemia is poorly understood. Data from studies in vitro suggest that volatile anesthetics release a vasodilator prostanoid. We hypothesized that prostanoids and nitric oxide (NO) are mediators of this response in vivo. If true, inhibition of cyclooxygenase by indomethacin (5 mg/kg intravenously) or of nitric oxide synthase by N(ω)-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 isoflurane was tested at three time points (0, 90, and 180 min) in pentobarbital-anesthetized pigs. Isoflurane challenges were separated by 60-min periods of continuous intravenous pentobarbital alone. Control animals (n = 7) received no additional pharmacologic intervention. Experimental animals were randomized to receive L-NAME before the second and indomethacin before the third isoflurane challenge (n = 7); L-NAME before the second and L-arginine (400 mg/kg intravenously) before the third isoflurane challenge (n = 9); or indomethacin before the second and L-NAME before the third isoflurane challenge (n = 8). Results: In control animals, isoflurane 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 isoflurane. 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.

Original languageEnglish (US)
Pages (from-to)1328-1337
Number of pages10
JournalAnesthesiology
Volume80
Issue number6
DOIs
StatePublished - Jan 1 1994

Keywords

  • Anesthetics, gases: nitric oxide
  • Anesthetics, volatile: isoflurane
  • Brain: cerebral blood flow; cerebral metabolic rate of oxygen consumption
  • Inhibitors, cyclooxygenase: indomethacin
  • Vasodilation: endothelium-dependent
  • Vasodilators: prostanoids

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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    Moore, L. E., Kirsch, J. R., Helfaer, M. A., Tobin, J. R., McPherson, R. W., & Traystman, R. J. (1994). Nitric oxide and prostanoids contribute to isoflurane-induced cerebral hyperemia in pigs. Anesthesiology, 80(6), 1328-1337. https://doi.org/10.1097/00000542-199406000-00021