Oxygen uptake of isolated toad skin epithelium: micromeasurement and effect of ionic acclimation.

Détails

ID Serval
serval:BIB_52544AA85E39
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Oxygen uptake of isolated toad skin epithelium: micromeasurement and effect of ionic acclimation.
Périodique
American Journal of Physiology. Cell Physiology
Auteur(s)
Raddatz E., Katz U., Kucera P.
ISSN
0363-6143 (Print)
ISSN-L
0002-9513
Statut éditorial
Publié
Date de publication
1991
Volume
260
Numéro
5 Pt 1
Pages
C1117-C1124
Langue
anglais
Résumé
Oxidative metabolism of isolated toad skin epithelium (Bufo viridis) was investigated in vitro under open-circuit conditions using the spectrophotometric oxyhemoglobin micromethod. This highly sensitive technique has been adapted for studying several epithelia in parallel and for detecting possible regional variations of oxygen uptake in individual epithelium. Changes in the proportion of mitochondria-rich cells (MRC) by ionic acclimation affected oxidative metabolism under nontransporting condition. After acclimation of animals to either NaNO3 or NaCl solutions (100 mmol/l, for greater than 2 wk), the number of MRC per square millimeter in epithelia from nonacclimated and NaNO3- and NaCl-acclimated animals was 350 +/- 113, 460 +/- 196, and 107 +/- 52, respectively. O2 uptake of nonacclimated and NaNO3-acclimated epithelia was significantly higher than that of NaCl-acclimated epithelia (i.e., 0.89 and 0.90 vs. 0.57 nmol O2.h-1.mm-2, respectively). The correlation established between O2 uptake and number of MRC allowed evaluation of the respiration rate of one single MRC, i.e., approximately 1 pmol O2/h. The lowest mitochondrial oxidative activity was found in the epithelia from NaCl-acclimated toads where the uncoupler 2,4-dinitrophenol (50 mumols/l) had the highest relative stimulatory effect (+114%). Acetazolamide (50 mumols/l), a potent inhibitor of carbonic anhydrase mainly present in the MRC, reduced selectively by 31% O2 uptake of the MRC-rich epithelia (NaNO3 acclimated). O2 uptake increased significantly by approximately 80% when basolateral pH increased from 5.8 to 7.8, but did not depend on apical pH. These findings indicate that under nontransporting (open-circuit) conditions, aerobic metabolism of the isolated toad skin epithelium is related to the density and/or characteristics of the MRC.(ABSTRACT TRUNCATED AT 250 WORDS)
Mots-clé
Acclimatization, Animals, Bufonidae, Cell Membrane/physiology, Epithelium/physiology, Hydrogen-Ion Concentration, Oxygen Consumption, Oxyhemoglobins/metabolism, Skin Physiological Phenomena, Spectrophotometry/instrumentation, Spectrophotometry/methods, Temperature
Pubmed
Web of science
Création de la notice
24/01/2008 14:19
Dernière modification de la notice
03/03/2018 17:13
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