Characterization of branchial transepithelial calcium fluxes in freshwater trout, Salmo gairdneri

Journal Article · Tue Mar 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:7101029

Perry, S F; Flik, G ^[1]

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1. Univ. of Ottawa, Ontario (Canada)

Experiments were performed to determine whether gill transepithelial calcium fluxes in the freshwater trout (Salmo gairdneri) are passive or require active transport and to characterize the mechanism involved. A comparison of the in vivo unidirectional flux ratios with the flux ratios calculated according to the transepithelial electrochemical gradients revealed that calcium uptake from the water requires active transport of Ca{sup 2+}. The inhibition of calcium uptake by external lanthanum, the specific deposition of lanthanum on the apical surface of chloride cells, and the favorable electrochemical gradient for calcium across the apical membrane suggest that the initial step in branchial calcium uptake is the passive entry of calcium into the cytosol of chloride cells through apical channels that are permeable to calcium. The study of gill basolateral plasma membrane vesicles demonstrated the existence of a high-affinity calmodulin-dependent calcium-transporting system. This system actively transports calcium from the cytosol of chloride cells into the plasma against a sizeable electrochemical gradient, thereby completing the transepithelial uptake of calcium. Calcium efflux occurs passively through paracellular pathways between chloride cells and adjacent pavement cells or between neighboring pavement cells.

• OSTI ID: 7101029
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 254:3; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ADULTS
AGE GROUPS
ALDEHYDES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
AQUATIC ORGANISMS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
CARBOHYDRATES
CARBON 14 COMPOUNDS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
ELECTRON MICROSCOPY
ENZYMES
EVEN-ODD NUCLEI
FISHES
GILLS
HALIDES
HALOGEN COMPOUNDS
HEXOSES
HISTOLOGY
HYDROLASES
IN VIVO
INTERMEDIATE MASS NUCLEI
IONS
ISOTOPES
LABELLED COMPOUNDS
LANTHANUM CHLORIDES
LANTHANUM COMPOUNDS
MANNOSE
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
MEMBRANES
MICROSCOPY
MONOSACCHARIDES
NUCLEI
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PROTEINS
RADIOISOTOPES
RARE EARTH COMPOUNDS
RESPIRATORY SYSTEM
SACCHARIDES
TRANSMISSION ELECTRON MICROSCOPY
TROUT
VERTEBRATES