caa a22 4500 469081899 CHVBK 20180323132952.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF00319161 doi (NATIONALLICENCE)springer-10.1007/BF00319161 Evidence for a morphological component in acid-base regulation during environmental hypercapnia in the brown bullhead ( Ictalurus nebulosus ) [Elektronische Daten] [Greg Goss, Pierre Laurent, Steve Perry] Summary: Exposure of adult brown bullheads Ictalurus nebulosus (120-450 g) to environmental hypercapnia (2% carbon dioxide in air) and subsequent recovery caused transient changes in whole body net sodium flux (J net Na+ ) and net chloride flux (J net Cl- ) resulting largely from changes in whole body sodium influx (J in Na+ ) and chloride influx (J in Cl- ). Scanning electron microscopy (SEM) revealed that the fractional area of chloride cells (CCs) on the interlamellar regions was reduced by 95% during environmental hypercapnia. During post-hypercapnic recovery, gill filament CC fractional area increased. The changes in J in Cl- during and after environmental hypercapnia were closely associated with the changes in CC fractional area while the changes in J in Na+ did not correspond to the changes in CC fractional area. Transmission electron microscopy (TEM) supported the SEM observations of CC surface area changes and demonstrated that these changes were caused by covering/uncovering by adjacent pavement cells (PVCs). Lamellar and filament PVC microvilli density increased during hypercapnia while there was a subsequent reduction in the post-hypercapnic period. These data suggest that an important mechanism of acid-base regulation during hypercapnic acidosis is modification of the chloride cell-associated Cl-/HCO 3 - exchange mechanism. We suggest that bullheads vary availability, and thus functional activity, of this transporter via reversible morphological alterations of the gill epithelium. The increase in density of PVC microvilli may be associated with sodium uptake and/or acidic equivalent excretion during acidosis. Springer-Verlag, 1992 Chloride cells nationallicence Pavement cells nationallicence Acid-base regulation nationallicence Hypercapnia nationallicence Gills nationallicence Ictalurus nebulosus (Teleostei) nationallicence Goss Greg Department of Biology, University of Ottawa, 30 George Glinski, K1N 6N5, Ottawa, Ontario, Canada aut Laurent Pierre Laboratoire de Morphologie Fonctionelle et Ultrastructure des Adaptations, CNRS, F-67037, Strasbourg, France aut Perry Steve Department of Biology, University of Ottawa, 30 George Glinski, K1N 6N5, Ottawa, Ontario, Canada aut Cell and Tissue Research Springer-Verlag 268/3(1992-06-01), 539-552 0302-766X 268:3<539 1992 268 441 https://doi.org/10.1007/BF00319161 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00319161 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Goss Greg Department of Biology, University of Ottawa, 30 George Glinski, K1N 6N5, Ottawa, Ontario, Canada aut NATIONALLICENCE 700 1- Laurent Pierre Laboratoire de Morphologie Fonctionelle et Ultrastructure des Adaptations, CNRS, F-67037, Strasbourg, France aut NATIONALLICENCE 700 1- Perry Steve Department of Biology, University of Ottawa, 30 George Glinski, K1N 6N5, Ottawa, Ontario, Canada aut NATIONALLICENCE 773 0- Cell and Tissue Research Springer-Verlag 268/3(1992-06-01), 539-552 0302-766X 268:3<539 1992 268 441 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer