Open AccessEffects of Halothane Anesthesia on Vasoconstrictor Response to NG-Nitro-L-Arginine Methyl Ester, an Inhibitor of Nitric Oxide Synthesis, in Sheep
Author(s) -
J. Meyer,
Christopher W. Lentz,
David N. Herndon,
Sharon H. Nelson,
Lillian D. Traber,
Daniel L. Traber
Publication year - 1993
Publication title -
anesthesia and analgesia/anesthesia and analgesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.404
H-Index - 201
eISSN - 1526-7598
pISSN - 0003-2999
DOI - 10.1213/00000539-199312000-00023
Subject(s) - halothane , medicine , nitric oxide , anesthesia , bolus (digestion) , nitroarginine , vascular resistance , nitric oxide synthase , endocrinology , pharmacology , hemodynamics
This study tests the hypothesis that halothane-induced inhibition of the endothelium-derived relaxing factor/nitric oxide (EDRF/NO) pathway significantly contributes to cardiovascular performance and thus reduces the vasoconstrictor response to NO synthesis inhibitors in vivo. We determined the effects of the administration of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in chronically instrumented, halothane-anesthetized sheep and in awake control animals. Six sheep underwent halothane anesthesia (1.5 vol%) with mechanical ventilation. Five sheep were studied in the awake state with spontaneous breathing. Both groups received a bolus of L-NAME (25 mg/kg), followed 4 h later by L-arginine (300 mg/kg) to reverse the effects of L-NAME. L-NAME administration caused a significant increase in pulmonary and systemic vascular resistance (P < 0.05) in both groups. However, L-NAME produced a sharp increase in mean arterial and pulmonary artery pressures only in the control group, whereas the pressor response in the halothane group was attenuated. Cardiac output, which was significantly lower after L-NAME administration in both groups, increased after L-arginine. The results suggest that halothane does not significantly alter the EDRF/NO-mediated effects on the vasculature but potentiates the cardiac depressant effect of L-NAME.