Effect of prior O2 breathing on ventilatory response to sustained isocapnic hypoxia in adult humans

• Published in: Journal of applied physiology (1985) Vol. 81; no. 4; pp. 1627 - 1632
• Main Authors: Honda, Y, Tani, H, Masuda, A, Kobayashi, T, Nishino, T, Kimura, H, Masuyama, S, Kuriyama, T
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.10.1996; American Physiological Society
• Subjects: Administration, Inhalation; Adult; Biological and medical sciences; Carbon Dioxide - blood; Cardiorespiratory control. Arterial mecano- and chemoreceptor; Female; Fundamental and applied biological sciences. Psychology; Glutamic Acid - blood; Glutamine - blood; Hormones - blood; Humans; Hypoxia - physiopathology; Male; Neurotransmitter Agents - blood; Oxygen - administration & dosage; Oxygen - blood; Oxygen - pharmacology; Plasma - chemistry; Plasma - metabolism; Respiratory Function Tests; Respiratory Mechanics - drug effects; Vertebrates: respiratory system; Human; Oxygen; Ventilatory response; Excitatory aminoacid; Neurotransmitter; Environmental factor; Hypoxia; Respiration; Glutamate; Chemoreceptor; Glutamine
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1996.81.4.1627

Y. Honda, H. Tani, A. Masuda, T. Kobayashi, T. Nishino, H. Kimura, S. Masuyama, and T. Kuriyama Departments of Physiology, Anesthesiology, and Chest Medicine, School of Medicine, Chiba University, and Department of Physical Therapy, International University of Health and Welfare, Ohdawara 324, Japan Received 5 December 1995; accepted in final form 13 May 1996. Honda, Y., H. Tani, A. Masuda, T. Kobayashi, T. Nishino, H. Kimura, S. Masuyama, and T. Kuriyama. Effect of prior O 2 breathing on ventilatory response to sustained isocapnic hypoxia in adult humans. J. Appl. Physiol. 81(4): 1627-1632, 1996. Sixteen healthy volunteers breathed 100% O 2 or room air for 10 min in random order, then their ventilatory response to sustained normocapnic hypoxia (80% arterial O 2 saturation, as measured with a pulse oximeter) was studied for 20 min. In addition, to detect agents possibly responsible for the respiratory changes, blood plasma of 10 of the 16 subjects was chemically analyzed. 1 ) Preliminary O 2 breathing uniformly and substantially augmented hypoxic ventilatory responses. 2 ) However, the profile of ventilatory response in terms of relative magnitude, i.e., biphasic hypoxic ventilatory depression, remained nearly unchanged. 3 ) Augmented ventilatory increment by prior O 2 breathing was significantly correlated with increment in the plasma glutamine level. We conclude that preliminary O 2 administration enhances hypoxic ventilatory response without affecting the biphasic response pattern and speculate that the excitatory amino acid neurotransmitter glutamate, possibly derived from augmented glutamine, may, at least in part, play a role in this ventilatory enhancement. normocapnia; mild hypoxia; glutamine-glutamate system 0161-7567/96 $5.00 Copyright © 1996 the American Physiological Society