title: In vivo support for the new concept of pulmonary blood flow-mediated CO2 gas excretion in the lungs.
abstract: To further examine the validity of the proposed concept of pulmonary blood flow-dependent CO2 gas excretion in the lungs, we investigated the effects of intramediastinal balloon catheterization-, pulmonary artery catheterization-, or isoprenaline (ISP)-induced changes in pulmonary blood flow on the end-expiratory CO2 gas pressure (PeCO2 ), the maximal velocity of the pulmonary artery (Max Vp), systemic arterial pressure, and heart rate of anesthetized rabbits. We also evaluated the changes in the PeCO2 in clinical models of anemia or pulmonary embolism. An almost linear relationship was detected between the PeCO2 and Max Vp. In an experiment in which small pulmonary arteries were subjected to stenosis, the PeCO2 fell rapidly, and the speed of the reduction was dependent on the degree of stenosis. ISP produced significant increases in the PeCO2 of the anesthetized rabbits. Conversely, treatment with piceatannol or acetazolamide induced significant reductions in the PeCO2 . Treatment with a cell surface F1/FO ATP synthase antibody caused significant reductions in the PeCO2 itself and the ISP-induced increase in the PeCO2 . Neither the PeCO2 nor SAP was significantly influenced by marked anemia [%hematocrit (Ht), 70 ∼ 47%]. On the other hand, in the presence of less severe anemia (%Ht: 100 ∼ 70%) both the PeCO2 and SAP fell significantly when the rabbits' blood viscosity was decreased. The rabbits in which pulmonary embolisms were induced demonstrated significantly reduced PeCO2 values, which was compatible with the lowering of their Max Vp. In conclusion, we reaffirm the validity of the proposed concept of CO2 gas exchange in the lungs.
authors.affiliation: Department of Physiology, Shinshu University School of Medicine, Matsumoto, Japan; Department of Innovation of Medical and Health Sciences Research, Shinshu University School of Medicine, Matsumoto, Japan;
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Kawai
authors.affiliation: Department of Physiology, Shinshu University School of Medicine, Matsumoto, Japan;
authors.forename: Kumiko
authors.initials: K
authors.lastname: Ajima
authors.affiliation: Department of Physiology, Shinshu University School of Medicine, Matsumoto, Japan;
authors.forename: Maki
authors.initials: M
authors.lastname: Kaidoh
authors.affiliation: Department of Innovation of Medical and Health Sciences Research, Shinshu University School of Medicine, Matsumoto, Japan;
authors.forename: Masao
authors.initials: M
authors.lastname: Sakaguchi
authors.affiliation: Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Japan; and.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Japan; and.
authors.forename: Mikito
authors.initials: M
authors.lastname: Kawamata
authors.affiliation: Hitachi Aloka Medical, Tokyo, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Physiology, Shinshu University School of Medicine, Matsumoto, Japan; Department of Innovation of Medical and Health Sciences Research, Shinshu University School of Medicine, Matsumoto, Japan; ohhashi@shinshu-u.ac.jp.
authors.forename: Toshio
authors.initials: T
authors.lastname: Ohhashi
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism*; D004452:Echocardiography; D006339:Heart Rate; D006439:Hemodynamics; D008168:Lung / Q000098:blood supply* / Q000378:metabolism*; D008297:Male; D011651:Pulmonary Artery / Q000378:metabolism*; D011659:Pulmonary Gas Exchange; D011817:Rabbits
chemical_list: D002245:Carbon Dioxide
keywords: acetazolamide; carbon dioxide gas excretion; cell surface F1/Fo adenosine 5′-triphosphate synthase; piceatannol; pulmonary circulation