Supplementary material from "Functional support for a novel mechanism that enhances tissue oxygen extraction in a teleost fish"

• Main Authors: T. S. Harter, F. S. Zanuzzo, C. T. Supuran, A. K. Gamperl, C. J. Brauner
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Figshare 2019
• Subjects: Biochemistry; Physiology; FOS Biological sciences; Atlantic salmon
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.4508273.v2; https://rs.figshare.com/collections/Supplementary_material_from_Functional_support_for_a_novel_mechanism_that_enhances_tissue_oxygen_extraction_in_a_teleost_fish_/4508273/2

A successful spawning migration in salmon depends on their athletic ability, and thus on efficient cardiovascular oxygen (O 2 ) transport. Most teleost fishes have highly pH-sensitive haemoglobins (Hb) that can release large amounts of O 2 when the blood is acidified at the tissues. We hypothesized that plasma-accessible carbonic anhydrase (paCA; the enzyme that catalyses proton production from CO 2 ) is required to acidify the blood at the tissues and promote tissue O 2 extraction. Previous studies have reported an elevated tissue O 2 extraction in hypoxia-acclimated teleosts that may also be facilitated by paCA. Thus, to create experimental contrasts in tissue O 2 extraction, Atlantic salmon were acclimated to normoxia or hypoxia (40% air saturation for more than six weeks), and the role of paCA in enhancing tissue O 2 extraction was tested by inhibiting paCA at rest and during submaximal exercise. Our results show that: (i) in both acclimation groups, the inhibition of paCA increased cardiac output by one-third, indicating a role of paCA in promoting tissue O 2 extraction during exercise, recovery and at rest; (ii) the recruitment of paCA was plastic and increased following hypoxic acclimation; and (iii) maximal exercise performance in salmon, and thus a successful spawning migration, may not be possible without paCA.