Nitric oxide and prostanoids contribute to isoflurane-induced cerebral hyperemia in pigs.
Publication/Presentation Date
6-1-1994
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 omega-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.
Volume
80
Issue
6
First Page
1328
Last Page
1337
ISSN
0003-3022
Published In/Presented At
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
Disciplines
Medicine and Health Sciences | Pediatrics
PubMedID
7516628
Department(s)
Department of Pediatrics
Document Type
Article