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Role of polarization of gastric EMFs in evaluation of contemporary HCl models
Author(s) -
REHM W. S.,
CARRASQUER G.,
SCHWARTZ M.
Publication year - 1990
Publication title -
journal of internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.625
H-Index - 160
eISSN - 1365-2796
pISSN - 0954-6820
DOI - 10.1111/j.1365-2796.1990.tb01469.x
Subject(s) - polarization (electrochemistry) , concentration polarization , choline , membrane potential , biophysics , chemistry , analytical chemistry (journal) , membrane , chromatography , biochemistry , biology
. The neutral proton pump (NP) model postulates a neutral exchange of K + for H + across the secretory membrane and the electrogenic proton pump (EP) model an electrogenic proton pump. Previous evidence is briefly reviewed and polarization of EMFs by transmucosal voltage clamping ( VC ) is presented. During VC , open circuit potential difference ( PD ) ( V OC ) is obtained by breaking the circuit for 2 s (after dielectric capacitors have discharged). The magnitude of polarization in Cl − media is less than in Cl − ‐free media, presumably due to the high conductance of Cl − paths. The magnitude in Cl − ‐free media is from 35 to 50 mV for a VC of 100 mV (nutrient side positive). The Na + /K + ‐ATPase is not essential because with choline sulphate media polarization is typical. With Cl − ‐free media, V OC versus I H (H + rate) is exponential but ( VC ‐ V OC ) versus I H is linear. Polarization on the basis of the NP model would be due to changes in K + diffusion potentials. However, with 80 mM K + on both sides (Cl − ‐free media) polarization is typical. We conclude that polarization cannot be due to a change in K + diffusion potentials but to polarization of the EP model. The problem remains of how to incorporate the important finding of the H + /K + ‐ATPase into a model for the intact tissue.