title: Hypercapnia induced shifts in gill energy budgets of Antarctic notothenioids.
abstract: Mechanisms responsive to hypercapnia (elevated CO(2) concentrations) and shaping branchial energy turnover were investigated in isolated perfused gills of two Antarctic Notothenioids (Gobionotothen gibberifrons, Notothenia coriiceps). Branchial oxygen consumption was measured under normo- versus hypercapnic conditions (10,000 ppm CO(2)) at high extracellular pH values. The fractional costs of ion regulation, protein and RNA synthesis in the energy budgets were determined using specific inhibitors. Overall gill energy turnover was maintained under pH compensated hypercapnia in both Antarctic species as well as in a temperate zoarcid (Zoarces viviparus). However, fractional energy consumption by the examined processes rose drastically in G. gibberifrons (100-180%), and to a lesser extent in N. coriiceps gills (7-56%). In conclusion, high CO(2) concentrations under conditions of compensated acidosis induce cost increments in epithelial processes, however, at maintained overall rates of branchial energy turnover.
authors.affiliation: Alfred Wegener Institute for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570, Bremerhaven, Germany. katrin.deigweiher@googlemail.com
authors.forename: Katrin
authors.initials: K
authors.lastname: Deigweiher
authors.forename: Timo
authors.initials: T
authors.lastname: Hirse
authors.forename: Christian
authors.initials: C
authors.lastname: Bock
authors.forename: Magnus
authors.initials: M
authors.lastname: Lucassen
authors.forename: Hans O
authors.initials: HO
authors.lastname: Pörtner
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000818:Animals; D000864:Antarctic Regions; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005880:Gills / Q000502:physiology*; D006935:Hypercapnia / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010473:Perciformes / Q000502:physiology*; D014176:Protein Biosynthesis / Q000187:drug effects / Q000502:physiology; D012313:RNA / Q000096:biosynthesis; D056152:Respiratory Rate / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013696:Temperature
chemical_list: D003609:Dactinomycin; D010042:Ouabain; D012313:RNA; D003513:Cycloheximide; D000254:Sodium-Potassium-Exchanging ATPase