Mechanisms of acid release in isolated gas gland cells of the
european eel anguilla anguilla.
Pelster, Bernd.
Institut f[umlaut]ur Physiologie, Ruhr-Universit[umlaut]at Bochum,
44780 Bochum, FRG
APStracts 2:0102R, 1995.
Mechanisms of acid production and of acid release have been analyzed
in isolated gas gland cells of the eel swimbladder using a cytosensor
microphysiometer. Incubation of isolated cells with oxamic acid
caused a dose-dependent decrease in the rate of proton release. At
the highest oxamic acid concentration used (20 mmol x l-1) proton
release was reduced by about 40%; incubation with sodium fluoride (10
mmol x l-1) or removal of glucose from the extracellular medium
caused a 60% and 80% reduction, respectively. NaCN had little effect
on proton secretion. Proton release of isolated gas gland cells was
largely dependent on the extracellular sodium concentration, and this
sodium effect was in part inhibitable by amiloride. A 15 - 20%
reduction in the rate of proton secretion was observed in the
presence of DIDS, an inhibitor of anion exchange. Inhibition of
mammalian H+/K+-ATPase with omeprazole had no effect, while
bafilomycin, an inhibitor of vesicular H+-ATPase, induced a 25%
reduction in proton secretion. Ethoxzolamide, a membrane permeable
inhibitor of carbonic anhydrase, caused a 60% reduction in proton
secretion (KI = 54.4 nmol x l-1). Prontosil-dextran, a membrane
impermeable sulfonamide also reduced the proton release, thus
indicating the presence of a membrane-bound carbonic anhydrase facing
the extracellular space.
Received 15 November 1994; accepted in final form 31 March 1995.
APS Manuscript Number R660-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.