HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/4/R747    most recent 00104.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Izumizaki, M. Articles by Homma, I. Search for Related Content PubMed PubMed Citation Articles by Izumizaki, M. Articles by Homma, I.

MODEL ORGANISMS AND COMPARATIVE FUNCTIONAL GENOMICS

The affinity of hemoglobin for oxygen affects ventilatory responses in mutant mice with Presbyterian hemoglobinopathy

¹Department of Physiology, Showa University School of Medicine, Tokyo 142-8555; ²Department of Molecular Genetics, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015; and ³Department of Internal Medicine II, Nara Medical University, Kashihara 634-8522, Japan

Submitted 3 March 2003 ; accepted in final form 21 June 2003

The purpose of this study was to test whether chronically enhanced O₂ delivery to tissues, without arterial hyperoxia, can change acute ventilatory responses to hypercapnia and hypoxia. The effects of decreased hemoglobin (Hb)-O₂ affinity on ventilatory responses during hypercapnia (0, 5, 7, and 9% CO₂ in O₂) and hypoxia (10 and 15% O₂ in N₂) were assessed in mutant mice expressing Hb Presbyterian (mutation in the -globin gene, 108 Asn Lys). O₂ consumption during normoxia, measured via open-circuit methods, was significantly higher in the mutant mice than in wild-type mice. Respiratory measurements were conducted with a whole body, unrestrained, single-chamber plethysmograph under conscious conditions. During hypercapnia, there was no difference between the slopes of the hypercapnic ventilatory responses, whereas minute ventilation at the same levels of arterial P_CO2 was lower in the Presbyterian mice than in the wild-type mice. During both hypoxic exposures, ventilatory responses were blunted in the mutant mice compared with responses in the wild-type mice. The effects of brief hyperoxia exposure (100% O₂) after 10% hypoxia on ventilation were examined in anesthetized, spontaneously breathing mice with a double-chamber plethysmograph. No significant difference was found in ventilatory responses to brief hypoxia between both groups of mice, indicating possible involvement of central mechanisms in blunted ventilatory responses to hypoxia in Presbyterian mice. We conclude that chronically enhanced O₂ delivery to peripheral tissues can reduce ventilation during acute hypercapnic and hypoxic exposures.

hyperoxia; hypoxia; hypercapnia; tissue; breathing

This article has been cited by other articles:

				Y. Ohshima, M. Iwase, M. Izumizaki, T. Ishiguro, M. Kanamaru, H. Nakayama, F. Gejyo, and I. Homma Hypoxic ventilatory response during light and dark periods and the involvement of histamine H1 receptor in mice Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2007; 293(3): R1350 - R1356. [Abstract] [Full Text] [PDF]

				M. Kanamaru and I. Homma Compensatory airway dilation and additive ventilatory augmentation mediated by dorsomedial medullary 5-hydroxytryptamine 2 receptor activity and hypercapnia Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R854 - R860. [Abstract] [Full Text] [PDF]

				M. Izumizaki, M. Pokorski, and I. Homma Role of the carotid bodies in chemosensory ventilatory responses in the anesthetized mouse J Appl Physiol, October 1, 2004; 97(4): 1401 - 1407. [Abstract] [Full Text] [PDF]

				N. R. Prabhakar Regulation of breathing by tissue oxygen: evidence from mutant mice with Presbyterian hemoglobinopathy Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2003; 285(4): R724 - R724. [Full Text] [PDF]