Use it or lose it? Sablefish,Anoplopoma fimbria, a species representing a fifth teleostean group where the βNHE associated with the red blood cell adrenergic stress response has been secondarily lost

• DOI: 10.1242/jeb.038844
• Publication Date: 2010-04-16T16:44:26Z
• Authors: Jodie L. Rummer; Mani Roshan-Moniri; Shannon K. Balfry; Colin J. Brauner
• Keywords: Erythrocyte Indices; Erythrocytes; Sodium-Hydrogen Exchangers; Fishes; Isoproterenol; 04 agricultural and veterinary sciences; Adrenergic beta-Agonists; Eye; 630; 3. Good health; Oxygen; Osmotic Pressure; Animals; 0401 agriculture, forestry, and fisheries; 14. Life underwater

Like most teleosts, sablefish (Anoplopoma fimbria Pallas 1814) blood exhibits a moderate Root effect (~35% maximal desaturation), where reduction in pH dramatically reduces O(2) carrying capacity, mechanism important for oxygenating the eye and filling swim bladder (SB) teleosts. Although lack SB, we observed well-defined choroid rete at eye. The adrenergically mediated cell swelling typically associated with functional red (RBC) beta-adrenergic Na(+)/H(+) exchanger (betaNHE), which would normally protect RBC pH, thus transport, during generalized acidosis, was not blood. Neither isoproterenol (a beta-agonist) nor 8-bromo cAMP could elicit this response. Furthermore, osmotic shrinkage, known to stimulate NHEs general betaNHE other teleosts such as trout flounder, resulted no significant regulatory volume increase (RVI), further supporting absence of betaNHE. onset occurs much lower (6.83-6.92) than may be required transport acidosis vivo. Phylogenetically, represent fifth group exhibiting secondary or loss activity. However, have lost (unlike four groups), still function oxygenate retina, but low ensure haemoglobin (Hb)-O(2) binding is compromised respiratory surface an anomaly within framework evolution, that they possess eye, SB system.