ISSN:
1432-1424
Keywords:
frog skin
;
cell Na activity
;
membrane potential
;
Na pump flux
;
Na microelectrodes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Cell Na activity,a Na c , was measured in the short-circuited frog skin by simulaneous cell punctures from the apical surface with open-tip and Na-selective microelectrodes. Skins were bathed on the serosal surface with NaCl Ringer and, to reduce paracellular conductance, with NaNO3 Ringer on the apical surface. Under control conditionsa Na c averaged 8±2mm (n=9,sd). Apical addition of amiloride (20 μm) or Na replacement reduceda Na c to 3mm in 6–15 min. Sequential decreases in apical [Na] induced parallel reductions ina Na c and cell current,I c . On restoring Na after several minutes of exposure to apical Na-free solutionI c rose rapidly $$(\tilde〈 30\sec )$$ to a stable value whilea Na c increased exponentially, with a time constant of 1.8±0.7 min (n=8). Analysis of the time course ofa Na c indicates that the pump Na flux is linearly related toa Na c in the range 2–12mm. These results indicate thata Na c plays an important role in relating apical Na entry to basolateral active Na flux.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01869014
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