Jc. Del Valle et al., Impairment of H+-K+-ATPase-dependent proton transport and inhibition of gastric acid secretion by ethanol, AM J P-GAST, 280(6), 2001, pp. G1331-G1340
Citations number
34
Categorie Soggetti
da verificare
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
Ethanol (1-20% vol/vol) caused a dose-dependent reduction in the basal rate
of acid formation in isolated rabbit gastric glands with a calculated EC50
value of 4.5 +/- 0.2%. Ethanol also reduced ATP levels in isolated gastric
glands and in cultured parietal cells (EC50 : 8.8 +/- 0.4% and 8.5 +/- 0.2
%, respectively) and decreased both basal and forskolin-stimulated cAMP lev
els. In studies carried out in gastric gland microsomes, ethanol inhibited
the hydrolytic activity of H+-K+-ATPase (EC50 : 8.5 +/- 0.6%), increased pa
ssive proton permeability (EC50 : 7.9%), and reduced H+-K+-ATPase-dependent
proton transport (EC50 : 3%). Our results show that the inhibition of gast
ric acid secretion observed at low concentrations of ethanol (less than or
equal to5%) is mainly caused by the specific impairment of H+-K+-ATPase- de
pendent proton transport across cell membranes rather than inhibition of th
e hydrolytic activity of H+-K+-ATPase, reduction in the cellular content of
ATP, or increase in the passive permeability of membranes to protons, alth
ough these changes, in combination, must be relevant at concentrations of e
thanol greater than or equal to7%.