title: N omega-nitro-L-arginine methyl ester prevents cerebral hyperemia by inhaled anesthetics in dogs.
abstract: The mechanism by which halothane, isoflurane, and nitrous oxide increase cerebral blood flow (CBF) is unknown. We assessed the cerebrovascular effects of nitrous oxide (70%; n = 6), isoflurane (1 minimum alveolar anesthetic concentration: 1.4%; n = 6) or halothane (1 minimum alveolar anesthetic concentration: 0.8%; n = 6) before and after blockade of nitric oxide (NO) synthase with 40 mg/kg N omega-nitro-L-arginine methyl ester (L-NAME) intravenously in dogs with baseline pentobarbital anesthesia. Baseline CBF (microspheres) was determined after 1 h of pentobarbital anesthesia. Cerebral perfusion pressure (CPP) was maintained during inhaled anesthetic or L-NAME by either hemorrhage or inflation of an intra-aortic balloon. Before L-NAME, halothane and isoflurane increased CBF (40 +/- 4 to 56 +/- 6 mL.min-1 x 100 g-1 and 43 +/- 6 to 78 +/- 12 mL.min-1 x 100 g-1, respectively) with no change in cerebral oxygen consumption (baseline: halothane, 2.6 +/- 0.2; isoflurane, 2.0 +/- 0.2 mL.min-1 x 100 g-1). On the contrary, nitrous oxide increased CBF similarly (40 +/- 6 to 57 +/- 8 mL.min-1 x 100 g-1), but increased cerebral oxygen consumption (2.2 +/- 0.3 to 3.0 +/- 0.3 mL.min-1 x 100 g-1). L-NAME decreased blood flow in the neurohypophysis by 80% with no change in blood flow in other brain regions. After L-NAME, reexposure to nitrous oxide, halothane, or isoflurane resulted in no change in CBF.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology/Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland.
authors.forename: R W
authors.initials: RW
authors.lastname: McPherson
authors.forename: J R
authors.initials: JR
authors.lastname: Kirsch
authors.forename: L E
authors.initials: LE
authors.lastname: Moore
authors.forename: R J
authors.initials: RJ
authors.lastname: Traystman
mesh_terms: D000769:Anesthesia, Inhalation; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D001921:Brain / Q000098:blood supply*; D004285:Dogs; D006221:Halothane / Q000009:adverse effects*; D006940:Hyperemia / Q000139:chemically induced* / Q000517:prevention & control; D007530:Isoflurane / Q000009:adverse effects*; D019331:NG-Nitroarginine Methyl Ester; D009609:Nitrous Oxide / Q000009:adverse effects*
chemical_list: D001120:Arginine; D007530:Isoflurane; D009609:Nitrous Oxide; D006221:Halothane; D019331:NG-Nitroarginine Methyl Ester