Active and passive Ca2+ fluxes across cell membranes of the guinea-pig taenia coli
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
The exchange of Ca between the extracellular fluid and the cellular compartment has been investigated in smooth muscle cells of taenia coli. It was found that during the initial phase of metabolic depletion by DNP+IAA, the net inwards flux of Ca amounts to 0.02 pmol cm−2·sec−1. This increase might be proportional to the physiological calcium leak.
The study of the relation between the inwardly directed Na gradient and the cellular Ca content has revealed that this Na gradient exerts no effect during prolonged exposure to K-free solution and a very limited effect during exposure to Na-deficient solutions. The cellular45Ca release induced by metabolic inhibition is not affected by substituting Li or choline for Na.
The supplementary calcium which enters the cells during exposure to a solution at low temperature is extruded on returning to a solution at 35°C, even if the Na gradient is reversed.
This finding and the effects of metabolic inhibition indicate that Ca extrusion in smooth muscle cells is a process which depends on metabolism and which is not affected by the inwardly directed Na gradient.
- Baker, P. F.: Transport and metabolism of calcium ions in nerve. Progr. Biophys. mol. Biol.24, 177–223 (1972)
- Baker, P. F., Hodgkin, A. L., Ridgway, E. B.: Depolarization and calcium entry in squid axons. J. Physiol. (Lond.)218, 709–755 (1971)
- Blaustein, M. P., Hodgkin, A. L.: The effect of cyanide on the efflux of calcium from squid axons. J. Physiol. (Lond.)200, 497–527 (1969)
- Casteels, R., Droogmans, G., Hendrickx, H.: Membrane potential of smooth muscle cells in K-free solution. J. Physiol. (Lond.)217, 281–295 (1971)
- Casteels, R., Wuytack, F.: Aerobic and anaerobic metabolism in smooth muscle cells of taenia coli in relation to active ion transport. J. Physiol. (Lond.) (in the press, 1975)
- Casteels, R., van Breemen, C., Wuytack, F.: Effect of metabolic depletion on the membrane permeability of smooth muscle cells and its modification by La3+. Nature New Biology239, 249–251 (1972)
- Dipolo, R.: Calcium efflux from internally dialysed squid giant axons. J. gen. Physiol.62, 575–589 (1973)
- Filo, R. S., Bohr, D. F., Rüegg, J. C.: Glycerinated skeletal and smooth muscle: calcium and magnesium dependence. Science147, 1581–1583 (1965)
- Raeymaekers, L., Wuytack, F., Casteels, R.: Na−Ca exchange in taenia coli of the guinea-pig. Pflügers Arch.347, 329–340 (1974)
- Schatzmann, H. J., Vincenzi, F. F.: Calcium movements across the membrane of human red cells. J. Physiol. (Lond.)201, 369–395 (1969)
- van Breemen, C., Wuytack, F., Casteels, R.: Stimulation of45Ca efflux from smooth muscle cells by metabolic inhibition and high K-depolarization. Pflügers Arch.359, 183–196 (1975)
- van Breemen, C., Farinas, B. R., Casteels, R., Gerba, P., Wuytack, F., Deth, R.: Factors controlling cytoplasmic Ca2+ concentration. Phil. Trans. B265, 57–71 (1973)
- Active and passive Ca2+ fluxes across cell membranes of the guinea-pig taenia coli
Volume 359, Issue 3 , pp 197-207
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- Smooth Muscle
- Ca Extrusion
- Na Gradient
- Metabolic Inhibition
- Industry Sectors