Sodium and potassium movements in the unstriated muscle of the guinea‐pig taenia coli

Goodford, P. J.; Hermansen, Keld

doi:10.1113/jphysiol.1961.sp006778

Cited by 122 publications

(97 citation statements)

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“…A common assumption has previously been to equate W to the dry weight of the tissue (173 g/kg fresh wt. for the taenia (Goodford & Hermansen, 1961), but we took the slightly smaller value of 150 g/kg fresh wt. when recalculating the present observations since some of the dry weight may be extracellular.…”

Section: Discussionmentioning

confidence: 99%

The distribution of ions in the smooth muscle of the guinea‐pig taenia coli

Buck¹,

Goodford²

1966

The Journal of Physiology

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SUMMARY1. Tracer movements and ionic composition have been observed in the smooth muscle of the guinea-pig taenia coil in vitro at 4, and 350 C. The muscle was quiescent at 40 C, and did not show spontaneous electrical nor mechanical activity for 25 min after re-warming. It was therefore possible to make observations on the quiescent tissue at 350 C.2. The rate of loss of tracer sodium was sensitive to changes of temperature, with an average Qlo of 3-4 + 0-4 on warming in the range 4-350 C.Exponential analysis of 24Na efflux at 35°C showed an initial rapid phase, a second phase with ti = 2 min, and a slowly exchanging phase. The second phase was most sensitive to changes of temperature and contained 15 m-mole Na/kg fresh wt. The corresponding transmembrane flux in spontaneously active muscle at 35°C would then be 30 p-mole cm-2 sec-', and 20 % of the available metabolic energy would be needed to maintain this exchange. 3. The rate of loss of tracer sodium was reduced in potassium-free or sodium-free solutions, but the effects were not impressive.4. The cell size increased at 40 C, and fell again on warming while Na and Cl left the cell and K was taken up. Cell chloride content was linearly related to cell size.5. The observations are interpreted on the assumption that the cytoplasm is osmotically isotonic and electrically neutral, and that some Na, K and Cl are sequestered elsewhere in the tissue. It is concluded that the quiescent smooth-muscle cell membrane is rather more permeable to sodium than the skeletal-muscle cell membrane.

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Section: Discussionmentioning

confidence: 99%

The distribution of ions in the smooth muscle of the guinea‐pig taenia coli

Buck¹,

Goodford²

1966

The Journal of Physiology

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“…In normal Krebs solution the uptake of 24Na is very rapid, being complete within 5 min, and it is impossible to distinguish a cellular component of uptake (Goodford & Hermansen, 1961). To maximize the cellular exchange, Na-loaded tissues were used.…”

Section: Ana Uptakementioning

confidence: 99%

The use of lanthanum to estimate the numbers of extracellular cation‐exchanging sites in the guinea‐pig's taenia coli, and its effects on transmembrane monovalent ion movements.

Brading¹,

Widdicombe²

1977

The Journal of Physiology

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SUMMARY1. Tissues were allowed to equilibrate in a Tris-buffered Krebs solution and were then exposed to similar solutions containing up to 5 mM-La. La 3. Subtraction of the ions in the measured [14C]sucrose space from the total tissue ion contents led to estimates of the 'cellular' ion contents. The effects of 1 hr exposure to 5 mM-La on these were a loss of 12*9 + 2*4 m-equiv/kg of cation and a gain of 10 0 + 2-6 m-equiv/kg of Cl.4. Similar changes in ion content were produced by La on 'Na-loaded' and 'K-loaded' tissues, these being tissues which by exposure to K-free or Na-free (high K) solutions had replaced all their K with Na or vice versa.5. The uptakes of 24Na and 36CI by Na-loaded tissues were both describable as the sum of two exponential processes: a fast component (t* I min), which was presumed to be extracellular and a slower, presumed transmembrane, component. La reduced the rapid component of uptake of 24Na by an amount greater than that predicted by the reduction in the e.c.s., the extra amount lost being some 10-15 m-equiv/kg. La also reduced the amount of rapidly exchanging 3601, but this reduction was entirely accounted for by the change in the e.c.s. La reduced the rate constant of the slow component of 24Na uptake.A. F. BRADING AND J. H. WIDDICOMBE 6. La reduced the rapidly exchanging component of 42K uptake by normal tissues by an amount equivalent to about 0.5 m-mole/kg fresh wt. of K in excess of the change in the extracellular space.7. La had little effect on the effluxes of 36CI and 42K from normal tissues. However, it reduced the size of the fastest component of exchange of 42K efflux from K-loaded tissues by an amount equal to some 10-15 m-equiv/kg in excess of the reduction in the e.c.s. A similar reduction in the rapidly exchanging component of 24Na efflux from normal tissues was also seen. La slowed the efflux of 24Na from Na-loaded tissues at times when the tracer lost could safely be regarded as intracellular.8. The taenia coli when exposed to K-free solutions gains Na and loses K. In the presence of La the gain in Na was completely blocked. K was still lost, however, being accompanied by Cland increased shrinkage. La also prevented the uptake of Na from high Na media by ion-depleted tissues (produced by exposure to sucrose media), while having little effect on the uptake of K from high K media by such tissues.9. The cation displaced by La in excess of that lost due to the reduction of the e.c.s. was shown by tracer studies to be rapidly exchanging. It is concluded that this cation, amounting to some 15-20 m-equiv/kg, is bound to fixed extracellular negative sites.

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“…4) instead of the curve normally found. It has been suggested that the curvature normally observed is due to an inhomogeneous distribution of potassium in the tissue (Goodford & Hermansen, 1961;Bauer et al, 1963;Buck & Goodford, 1966), and the present observations might indicate that more of the tissue potassium is exchangeable in the presence of adrenaline than under control conditions. They might alternatively be due to a changed ratio of cell volume to cell surface area, as has previously been observed by Freeman-Narrod & Goodford (1962).…”

Section: "K-uptakementioning

confidence: 51%

“…The extracellular space was determined using three different substances (Goodford & Hermansen, 1961;Goodford & Lullmann, 1962;Goodford & Leach, 1964). Table I shows that adrenaline always increased the extracellular space in both isometric and isotonic conditions.…”

Section: Resultsmentioning

confidence: 99%

“…The methods used to study the ionic composition were essentially those of Goodford & Hermansen (1961) and Freeman-Narrod & Goodford (1962). Three or more guinea-pigs were used in each experiment, from each of which six or more pieces of taenia coli 25 mm long were dissected as quickly as possible, weighed to give the fresh weight, and suspended in a modified Krebs solution (mM): Na+ 137, K+ 5.9, Mg2+ 1.2, Ca2+ 2.5, Cl-134, H2PO-1.2, HCO-3 15.5 and dextrose 11.5, equilibrated with 97% 02/3% CO2.…”

Section: Methodsmentioning

confidence: 99%

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