Publication Date:
2013-06-15
Description:
The Root effect is a pH-dependent reduction in hemoglobin-O2 carrying capacity. Specific to ray-finned fishes, the Root effect has been ascribed specialized roles in retinal oxygenation and swimbladder inflation. We report that when rainbow trout are exposed to elevated water carbon dioxide (CO2), red muscle partial pressure of oxygen (PO2) increases by 65%--evidence that Root hemoglobins enhance general tissue O2 delivery during acidotic stress. Inhibiting carbonic anhydrase (CA) in the plasma abolished this effect. We argue that CA activity in muscle capillaries short-circuits red blood cell (RBC) pH regulation. This acidifies RBCs, unloads O2 from hemoglobin, and elevates tissue PO2, which could double O2 delivery with no change in perfusion. This previously undescribed mechanism to enhance O2 delivery during stress may represent the incipient function of Root hemoglobins in fishes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rummer, Jodie L -- McKenzie, David J -- Innocenti, Alessio -- Supuran, Claudiu T -- Brauner, Colin J -- New York, N.Y. -- Science. 2013 Jun 14;340(6138):1327-9. doi: 10.1126/science.1233692.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada. jodie.rummer@jcu.edu.au〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23766325" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Carbon Dioxide/metabolism
;
Erythrocytes/metabolism
;
Hemoglobins/*metabolism
;
Hydrogen-Ion Concentration
;
Muscle, Skeletal/metabolism
;
Oncorhynchus mykiss/*blood/*metabolism
;
Oxygen/*blood/*metabolism
;
Partial Pressure
;
Stress, Physiological
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
