Edmund Y. Tong

An investigation of sodium transport in barnacle muscle fibres by means of the microsyringe technique

1. The cation composition of single barnacle muscle fibres following damage by axial insertion of a microsyringe has been measured. The Na and Ca contents of these fibres were raised.

On the mode of action of ethacrynic acid, using the barnacle muscle fiber as a model

Abstract External application of 10−4 M ethacrynic acid at pH 7.8 is usually without effect on the Na efflux into a 10 mM HCO3− solution. At an external pH of 6.8, however, 10−3 M ethacrynic acid causes a gradual rise in the loss of Na into a solution the initial HCO3- concentration of which is 5 mM. Lowering the external pH of this solution to 5.8 results in a reversal of the slow rise in Na loss. External application of 10−5 M ethacrynic at pH 6.9 and pH 6.3 is unaccompanied by a rise in the Na efflux into a Ca2+-free solution the initial HCO3− concentration of which is 5 mM. External application of 10−3 M ethacrynic acid following stimulation of the Na efflux into a Ca2+-free solution by reducing the external pH from 7.8 to 6.3 results in a large fall in the rate of loss of Na. These results indicate that the CO2-sensitive Na efflux is the principal site at which ethacrynic acid acts.

Stimulation by caffeine of the calcium efflux in barnacle muscle fibers

Die Befunde ergeben, dass einzelne Muskelfasern der Entenmuschel durch Mikroinjektion mit45Ca aufgeladen werden können. Eine Umspülung der Muskelfasern mit einer coffeinhaltigen Lösung bewirkt ein stärkeres Ausströmen des Calciums als eine Mikroinjektion des Coffeins in die Fasern direkt.

The effect of diphenylhydantoin on sodium efflux from single barnacle muscle fibers

Abstract Diphenylhydantoin is shown to reduce the Na efflux in single bernacle muscle fibers. The magnitude of the inhibiting effect is 38%, which is slightly more than half that of ouabain. The results are explained by supposing that the action of diphenylhydantoin on the transport enzyme is incomplete or that its main point of action is the T-system.

Tris as a blocking agent of the proton-sensitive component of the sodium efflux in barnacle muscle fibers

Studien über den Natriumtransport in den Muskeln vonBalanus sp. haben bewiesen, dassTris den protonempfindlichen Anteil der Natrium-Pumpe verlangsamt und dasTris hauptsächlich an der Aussenseite des Sarkolemms aktiv ist.

The influence of caffeine on the sodium efflux in barnacle muscle fibers.

Nachweis, dass Coffein zunächst den Auswärtstrom von Na-Ionen aus Einzelfasern der Bernakelmuskeln verringert, ihn hernach aber zu steigern vermag.

Diphenylhydantoin as a blocking agent of the proton-sensitive component of Na efflux in barnacle muscle fibers

Abstract Earlier experiments with barnacle muscle fibers had indicated that ouabain is a more powerful inhibitor of the Na pump than diphenylhydantoin (DPH), and that the ouabain-insensitive Na efflux is markedly stimulated by lowering the external pH, raising the external K concentration or by microinjecting CaCl 2 . In the present work the effect of acidification of the bathing medium before and after external application of DPH was investigated. This revealed that (i) the action of DPH is pH-dependent, and (ii) DPH blocks or inactivates the proton-sensitive component of the Na efflux.

Sensitivity of sodium efflux in barnacle muscle fibers to the microinjection of calcium chloride

Nachweis, dass der Auswärtsstrom von Natrium aus Muskelfasern der ArthropodenBalanus nubilus undBalanus aquila in künstlichem, kaliumfreiem Meerwasser durch Mikroinjektion von Kalziumchlorid aktiviert wird.

Sensitivity of the Na efflux in barnacle muscle fibres to the microinjection of troponin-C

Nachweis, dass eine Microinjektion von Troponin-C den Na-Ionen-Ausfluss aus Einzelfasern des Entenmuschel-Muskels steigert.

Inhibition of the CO2-sensitive Na efflux in barnacle muscle fibers by micro-injection of ethacrynic acid

Es wird gezeigt, dass die Mikroinjektion von Äthacrynsäure [2,3-Dichloro-4(2-methylenbatyryl)-phenoxyacetsäure] in die isolierte Muskelfaser der Entenmuschel nur dann den Natriumausstrom herabsetzt, wenn die Badelösung vorher angesäuert wird.