Measurement of cation fluxes in rat diaphragm

Creese, R.

doi:10.1098/rspb.1954.0039

Cited by 121 publications

(98 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By pooling experiments performed over different time intervals when the initial concentrations, rate constants, and influxes were similar, it was possible to show that the results were entirely consistent with the predictions of equation (6).…”

Section: Dtsupporting

confidence: 63%

“…If a combination of tracer and analytical data is used, it is apparent that a test of the theory is possible. Influx from tracer, the rate constant for tracer loss, the elapsed time interval, and the initial potassium content given by the control muscle determine the final potassium content according to equation (6). The values so calculated can be compared with the final measured analytical potassium content.…”

Section: Muscle Weight-mgmentioning

confidence: 99%

“…-1, and q~ = 10/~moles/gm hr. Plotting equation (6) for these values indicates that the loss is linear for the first 2 hrs. Therefore, for this time interval and the above conditions, the net flux could be obtained by dividing the initial-final concentration difference by the time interval with no error resulting.…”

Section: Dtmentioning

confidence: 99%

See 2 more Smart Citations

Tracer and Non-Tracer Potassium Fluxes in Frog Sartorius Muscle and the Kinetics of Net Potassium Movement

Sjodin

Henderson

1964

The Journal of General Physiology

View full text Add to dashboard Cite

Experiments were performed to test the applicability of permeability kinetics to whole frog sartorius muscle using K ¢ ions as tracers of potassium flux. The whole muscle was found to obey closely the kinetic laws expected to hold for single cellular units in which the potassium fluxes are membrane-limited and intracellular mixing is rapid enough not to introduce serious error. In a 5 mM K Ringer's solution, potassium effiux was very nearly equal to influx when the rate constant for K a loss was applied to the whole of the muscle potassium. Over a fairly wide range of external potassium concentration, the assumed unidirectional fluxes measured with tracer K a showed good agreement with net potassium changes determined analytically. The specific activity of potassium lost from labeled muscles to an initially K-free Ringer's solution was measured as a test of the adequacy of intracellular mixing. The results were those expected for a population of cells with uniformly distributed intracellular K ¢. A small deviation was encountered which can be attributed either to a dispersion of fiber sizes in the sartorius or to a possible small additional cellular compartment in each individual fiber. The additional cellular compartment, should it exist, contains from 0.5 to 1 per cent of the muscle potassium. This is evidently not large enough to interfere seriously with the applicability of permeability kinetics to the whole muscle. I N T R O D U C T I O NI o n fluxes have been previously measured in whole muscle b y m a n y investigators. T h e work has led to two main kinetic models for whole muscles. O n e model regards whole muscle as a population of single cellular units each obeying simple first-order permeability kinetics (Keynes, 1954; Creese, 1954). According to this model, the whole muscle will, with possible minor p e r t u r b ations, o b e y the same kinetics. T h e other model proposed regards whole muscle as an assemblage of cellular units in which simple permeability kinetics are not obeyed due to the presence of large perturbations caused b y slow diffusion intracellularly (Harris, 1957; Harris and Steinbach, 1956). For con-605

show abstract

Section: Dtsupporting

confidence: 63%

Section: Muscle Weight-mgmentioning

confidence: 99%

See 1 more Smart Citation

Tracer and Non-Tracer Potassium Fluxes in Frog Sartorius Muscle and the Kinetics of Net Potassium Movement

Sjodin

Henderson

1964

The Journal of General Physiology

View full text Add to dashboard Cite

show abstract

“…As can be seen from Table 1 there is a small increase in the water content of the immersed muscle compared with the controls in vivo, similar to that obtained by Creese (1954) and Creese, El-Shafie & Vrbova (1968). There is a large increase in the water content of perfused muscles as compared with controls in vivo.…”

Section: Resultssupporting

confidence: 69%

Decamethonium in the Perfused and Immersed Rat Diaphragm

Humphrey

1975

British J Pharmacology

View full text Add to dashboard Cite

1 The water content and mannitol space of rat diaphragms which were perfused through the inferior vena cava was increased compared with immersed diaphragms. The potassium content of both preparations, when expressed in terms of dry weight, was maintained at similar values to that found in vivo. 2 Despite the application of a constant concentration of decamethonium, a steady level of neuromuscular block was not obtained in either the perfused or immersed rat diaphragm. The immersed preparation differed from the perfused preparation in that recovery from paralysis occurred despite the continued presence of the drug. 3 The rate of uptake of labelled decamethonium (100 Mm) at the end-plate region was similar in the perfused and immersed diaphragm. The slopes of the regressions were 0.059 and 0.054 ,ul mg1min-' (based on dry weight) respectively which were not significantly different. This implies that the rate of uptake of the drug at the end-plate is slow and limited by the rate of entry into the fibre rather than by diffusion to the site of entry. IntroductionMethods Creese & Maclagan (1970) have obtained autoradiographic evidence that decamethonium enters muscle fibres in the rat. It has been suaggested that the permeability of this organic ion at the end-plate is low and similar to that of sodium (Creese & England, 1970). If this is the case, then the uptake of decamethonium would be expected to be limited by entry at the cell membrane rather than by diffusion. If however, the permeability of decamethonium approached that of potassium then the uptake would be faster in a perfused muscle than in an immersed muscle because of delays due to diffusion in the latter (Klaus, Luilman & Muscholl, 1960;Keynes, 1954). In the present study, rat diaphragms were perfused in vitro via the inferior vena cava with labelled drug to compare the rate of uptake with that in immersed muscles. In addition, the neuromuscular block produced by decamethonium was recorded in an attempt to confirm previous claims that a steady paralysis can be obtained with depolarizing drugs (Maclagan, 1962; Gibberd, 1966) when applied via the capillaries. The water, potassium and sodium content and also the mannitol space were determined in both preparations. Immersed diaphragmThe left anterior portion of the diaphragm together with its rib was quickly removed, with or without the left phrenic nerve and transferred to a bath (100 ml) for recording of contractions, or to a tube (10 ml) for measurement of uptake of labelled decamethonium. Twitch tension was recorded by means of a strain gauge connected to the tendon by a thin platinum wire (0.4 g). The uptake of the labelled drug was measured in the manner described by Creese & England (1970).After immersion in labelled drug the muscle was 368 P.P.A. HUMPHREY washed in saline for 10 min, attached to a metal strip and frozen on solid carbon dioxide. Perfused diaphlragmThe preparation is similar to that described by Gibberd (1966). The inferior vena cava was cannulated through the right auricle and the e...

show abstract

“…The muscle fibres themselves do not seem to undergo a detectable change in volume (Creese, 1954;Creese, D'Silva & Hashish, 1955). In this context the present findings, that the thickness of the diaphragms increases with time and that the tortuosity of the diffusion channels through the extracellular compartment decreases greatly, are explicable at least on a qualitative basis.…”

Section: Discussionmentioning

confidence: 51%