title: Role of nitric oxide in the regulation of oxygen consumption in conscious dogs.
abstract: The role of nitric oxide (NO) in the regulation of O2 consumption was studied in chronically instrumented conscious dogs. A specific NO synthesis inhibitor, nitro-L-arginine (NLA, 30 mg/kg i.v.), significantly increased mean arterial pressure from 100 +/- 4 to 134 +/- 5 mm Hg (mean +/- SEM) and total peripheral resistance by 157 +/- 16% and reduced cardiac output by 47 +/- 3% and heart rate by 34 +/- 6% after 120 minutes. Changes in arterial blood gases were not observed. There were significant changes in PO2 (-14 +/- 2 mm Hg), O2 saturation (-21 +/- 2%), the percentage of hemoglobin as oxyhemoglobin (-21 +/- 2%), and O2 content (-3.0 +/- 0.9 vol%) and a significant increase in percent reduced hemoglobin (21 +/- 1%) in mixed venous blood, associated with an increase in O2 extraction (5.1 +/- 0.2 vol%) (all P < .01). O2 consumption was increased from 124 +/- 6 to 155 +/- 9 mL/min (P < .05). Methoxamine, titrated to have hemodynamic effects similar to those of NLA (eg, mean arterial pressure increased from 97 +/- 4 to 131 +/- 5 mm Hg), had much smaller effects on venous blood gases, hemoglobin, and O2 extraction (2.3 +/- 0.7 vol%) and no significant effect on O2 consumption. NLA also caused an increase in O2 consumption of 37 +/- 8% (P < .01) in quietly resting conscious dogs that had undergone pretreatment with hexamethonium and atropine, but no significant change in O2 consumption in dogs anesthetized with barbiturate.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology, New York Medical College, Valhalla 10595.
authors.forename: W
authors.initials: W
authors.lastname: Shen
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.forename: M
authors.initials: M
authors.lastname: Ochoa
authors.forename: G
authors.initials: G
authors.lastname: Zhao
authors.forename: M S
authors.initials: MS
authors.lastname: Wolin
authors.forename: T H
authors.initials: TH
authors.lastname: Hintze
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002302:Cardiac Output; D003243:Consciousness; D004285:Dogs; D006439:Hemodynamics / Q000187:drug effects; D008729:Methoxamine / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase; D019335:Nitroarginine; D010101:Oxygen Consumption / Q000187:drug effects; D013997:Time Factors
chemical_list: D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D008729:Methoxamine