Gastric proton pump localization. Application of triphosphatase and monophosphatase techniques.

Abstract

Potassium-dependent phosphatase activity can be demonstrated in unfixed frozen sections of mouse stomach using either adenosine triphosphate (ATP) or p-nitrophenyl phosphate (NPP) as substrate. In both cases the potassiumdependent reaction is confined to oxyntic cells, but with ATP, a strong, potassium-independent reaction occurs in the connective tissue of the lamina propria and elsewhere. In the NPP system potassium-independent reaction is very slight, and the oxyntic cell reaction shows responses to Literature Cited

Communications

“…(Berglindh, Dibona, Ito & Sachs, 1980;Forte, Machen & Obrink, 1980). We have previously shown that a K+-dependent p-nitrophenyl phosphatase (K+-NPPase) identifiable with the phosphatase step of H+, K+-ATPase can be localized cytochemically by capture ofliberated inorganic phosphate using magnesium ions (Firth & Stranks, 1981). Using this method the site of K+-NPPase activity in parietal cells can be shown to be the canalicular region, a finding in accordance with current views on the mechanism of gastric acid secretion.…”

Adenosine triphosphate-lead histochemical reactions in ependymal epithelia of murine brains do not represent calcium transport adenosine triphosphatase

“…However, the enzymes work through alternate phosphorylation and dephosphorylation of enzyme protein by the terminal phosphate of the substrate, and all of them can accept various aromatic phosphates such as p-nitrophenyl phosphate as pseudo-substrates for the dephosphorylation step (Rega eta]., 1973;Hobbs & Albers, 1980). This forms the basis for the enzyme-histochemical methods for localization of Na+,K*-ATPase (Ernst, 1972a, b) and H +, K+-ATPase (Firth & Stranks, 1981). Although enzymes of this family may have specific individual inhibitors-such as ouabain for Na +, K+-ATPase and omeprazole for H +, K+-ATPase-they share the characteristic of dependence on sulphydryl groups for activity and are therefore all sensitive to inhibition by agents such as N-ethyl maleimide and p-hydroxymercuribenzoate (Firth, 1978).…”

Detection of ouabain-insensitive H(+)-transporting, K(+)-stimulated p-nitrophenylphosphatase activity in rat gastric glands by cerium-based cytochemistry.

“…The catalytic and antigenic sites of H-K ATPase are also known to be located in the plasma membrane of the microvilli and the limiting membrane of the tubulovesicular system of the parietal cells (Fujimoto et al, 1986;Koenig, 1984;Coulton and Firth, 1983;Smolka et al, 1983;Firth and Stranks, 1981;Saccomani et al, 1979;Rubin and Aliasgharpour, 1976). …”

“…The first successful attempt to determine the localization of this enzyme at the light microscopic level was done by Firth and Stranks (1981), using a modification of the strontium-lead method of Ernst (1972). Subsequently, Koenig (1984) employed a lead-based method derived from that of Mayahara et al (1980) for detection of Na-K ATPase activity by light and electron microscopy levels.…”