The asymmetrical stimulation of a membrane adenosine triphosphatase in relation to active cation transport

Whittam, R.

doi:10.1042/bj0840110

Cited by 344 publications

(69 citation statements)

References 17 publications

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“…This has not been measured in smooth muscle. But it has been shown that stretch increases the rate of loss of 42K (Born & Bulbring, 1956) as well as the rate of uptake, while the rate of loss of 24Na is reduced in the unstretched preparation (FreemanNarrod & Goodford, 1962 (Whittam, 1962), and thus the original ionic distribution is re-established. These mechanisms require a greater metabolic energy supply.…”

Section: Discussionmentioning

confidence: 99%

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

Bülbring¹,

Kuriyama²

1963

The Journal of Physiology

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The relaxation of intestinal smooth muscle by adrenaline is due to the cessation of the spontaneous discharge of action potentials which is associated with a rise in membrane potential (Biulbring, 1955;Burnstock, 1958). The magnitude of the hyperpolarization depends on the membrane potential prevailing at the moment when adrenaline is applied (Biilbring & Kuriyama, 1963). Though it is known that the membrane potential is related to the degree of stretch applied to the muscle it has not been possible in the past to set it with regularity at a certain level in different preparations, because the definition of the initial muscle length has been inadequate. Resting length cannot be determined because spontaneous activity prevents complete relaxation. In situ length depends on the spontaneous tone at the moment of excision. Thus preparations of equal in situ length, mounted at a certain length or at a certain tension, behave quite differently.The relation between muscle length and muscle tension is complicated by the active production of tension in response to stretch, which prevents the distinction between resting and active tension, the latter being an unknown fraction of the total tension recorded. On the other hand, tension is related to the cross-sectional area of the muscle. When the muscle is stretched, the deformation of the muscle fibres can be measured not only by the increase in length but also by the reduction in cross-sectional area. An estimate of this is given by the ratio of muscle weight (mg) to its length (mm). The W:L ratio takes into account the variable weight of different muscles, and thus it would be expected to provide the standard conditions required for the comparison of different preparations.In the present work reproducible conditions have been obtained by stretching the muscle to a given length in relation to its weight. Within certain limits the initial membrane potential as well as the changes produced by adrenaline were found to be proportional to the W:L ratio.

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Section: Discussionmentioning

confidence: 99%

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

Bülbring¹,

Kuriyama²

1963

The Journal of Physiology

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“…Active pumping of sodium across the red cell membrane is inhibited by the absence of extracellular potassium (Dunham & Glynn, 1961;Whittam, 1962). Insulin secretion was stimulated by incubation in a potassium-free medium, but the stimulation was sustained and not so great as that caused by ouabain.…”

Section: Introductionmentioning

confidence: 99%

The role of sodium and potassium in insulin secretion from rabbit pancreas

Hales¹,

Milner²

1968

The Journal of Physiology

162

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SUMMARY1. Insulin secretion from pieces of rabbit pancreas incubated in vitro was studied in media of different ionic composition and in response to different substances added to the media.2. Experiments were performed which demonstrated that a sodium pump played a role in insulin secretion and that inhibition of the pump by ouabain, or by the omission of extracellular potassium, stimulated insulin secretion.3. A rise in extracellular potassium concentration stimulated insulin secretion independently of changes in the osmolarity or sodium or chloride concentration of the incubation medium.4. The role of extracellular sodium in insulin secretion was investigated. Extracellular sodium was a pre-requisite for insulin secretion stimulated by glucose, glucagon, L-leucine, tolbutamide, potassium or ouabain.5. The presence of 3.3 mm glucose in the incubation medium was not essential for the stimulation of insulin secretion by L-leucine, tolbutamide or ouabain. Glucagon did not stimulate insulin secretion in the presence of 3-3 mm glucose but did so in the presence of 16-5 mm glucose.6. The results obtained in these experiments suggested that a transmembrane sodium flux probably in the , cell was a fundamental event in the stimulation of insulin secretion by diverse stimuli.

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“…A number of workers using non-nucleated erythrocytes have reported that different conditions at haemolysis and during resealing affect both the enzyme and protein composition as well as the permeability characteristics of the final 'ghost' preparation. These conditions include osmolarity, temperature, the concentration of bivalent cations and pH (Whittam, 1962;Dodge et al, 1963;Bramley & Coleman, 1972;Schwoch & Passow, 1973;Wessels & Verkamp, 1973). Previous studies had shown that pigeon erythrocyte 'ghosts' containing ATP and obelin could be prepared after haemolysis in 6mM-NaCI/3mM-MgCl2, pH7.0, and resealing for up to 90min at 37°C (Campbell & Dormer, 1975).…”

Section: Ca2" Contamination In the Mediamentioning

confidence: 99%

“…The 10mM-Tes was passed down a Chelex 100 column (Campbell & Dormer, 1975) (Whittam, 1962;Dodge et al, 1963;Bramley & Coleman, 1972;Schwoch & Passow, 1973;Wessels & Verkamp, 1973). Previous studies had shown that pigeon erythrocyte 'ghosts' containing ATP and obelin could be prepared after haemolysis in 6mM-NaCI/3mM-MgCl2, pH7.0, and resealing for up to 90min at 37°C (Campbell & Dormer, 1975).…”

Section: Ca2" Contamination In the Mediamentioning

confidence: 99%

Inhibition by calcium ions of adenosine cyclic monophosphate formation in sealed pigeon erythrocyte ‘ghosts’. A study using the photoprotein obelin

Campbell¹,

Dormer²

1978

Biochemical Journal

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1. Sealed pigeon erythrocyte 'ghosts' were prepared containing ATP and the Ca2+-activated photoprotein obelin to investigate the relationship between cyclic AMP formation and internal free Ca2+. 2. The 'ghosts' were characterized by (a) morphology (optical and electron microscopy), (b) composition (haemoglobin, K+, Na+, Mg2+, ATP, obelin), (c) permeability to Ca2 , assessed by obelin luminescence and (d) hormone sensitivity (the effect of f8-adrenergic agonists and antagonists on cyclic AMP formation). 3. The effect of osmolarity at haemolysis and ATP at resealing on these parameters was investigated. 4. Sealed 'ghosts', containing approx. 2% of original haemoglobin, 150mM-K+, 0.5mM-ATP, 103-104 obelin luminescence counts/106 'ghosts', which were relatively impermeable to Ca2+ and in which cyclic AMP formation was stimulated by f,-adrenergic agonists over a concentration range similar to that for intact cells, could be prepared after haemolysis in 6mM-NaCl/3n1M-MgCl2/50mM-Tes, pH7, and resealing for 30min at 37°C in the presence of ATP and 150mM-KCl. 5. The initial rate of adrenaline-stimulated cyclic AMP formation in these 'ghosts' was 30-50 % ofthat in intact cells and was inhibited by the addition of extracellular Ca2+. Addition of Ca2+ to the 'ghosts' resulted in a stimulation of obelin luminescence, indicating an increase in internal free Ca2+ under these conditions. 6. The ionophore A23187 increased the rate of obelin luminescence in the 'ghosts' and also inhibited the adrenaline-stimulated increase in cyclic AMP. 7. The effect of ionophore A23187 on obelin luminescence and on cyclic AMP formation in the 'ghosts' was markedly decreased by sealing EGTA inside the 'ghosts'. 8. It was concluded that cyclic AMP formation inside sealed pigeon erythrocyte 'ghosts' could be inhibited by more than 50% by free Ca2+ concentrations in the range 1-1O0uM.A considerable amount of indirect evidence exists that changes in intracellular Ca2+ play an important part in the action of certain hormones (Berridge, 1976;Hales et al., 1977;Rasmussen & Goodman, 1977). Investigations of the effects of Ca2+ on adenylate cyclase have mostly been carried out on brokencell preparations, in the absence of ionic gradients across the cell membrane, and have often involved the use of high non-physiological concentrations of Ca2+ (Hales et al., 1977). Although the concentration of intracellular free Ca2+ has only been measured in a few large cells such as barnacle muscle (Ashley & Ridgway, 1970) and the squid giant axon (Baker et al., 1971;Baker, 1972), it now seems likely that under physiological conditions the concentration of free Ca2+ in cells does not exceed 10pUM. In intact pigeon erythrocytes it has been reported that adenylate cyclase can be inhibited by concentrations of Ca2+ less than 10puM (Campbell & Siddle, 1976). Further progress in the investigation of interactions between Vol. 176 intracellular Ca2+ and cyclic nucleotides has been hampered by the lack of suitable preparations where it is possible to study directly changes in ...

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The asymmetrical stimulation of a membrane adenosine triphosphatase in relation to active cation transport

Cited by 344 publications

References 17 publications

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

The role of sodium and potassium in insulin secretion from rabbit pancreas

Inhibition by calcium ions of adenosine cyclic monophosphate formation in sealed pigeon erythrocyte ‘ghosts’. A study using the photoprotein obelin

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