Effects of noradrenaline, vasopressin and angiotensin on the Na‐K pump in rat isolated liver cells

Berthon, B; Capiod, Thierry; Claret, M

doi:10.1111/j.1476-5381.1985.tb09445.x

Cited by 25 publications

(17 citation statements)

References 40 publications

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“…At reduced [Ca2+]i, ac,-stimulation has no effect. This has been interpreted as removal of Ca2+ inhibition by al-stimulation (Berthon, Capiod & Claret, 1985): at low [Ca2+]i there is no inhibition of Ip, and a-stimulation thus has no effect. A similar explanation is unlikely in our experiments for the fl-induced pump stimulation, since this hypothesis provides no mechanism for the decrease in Ip induced by ISO at reduced [Ca2+]i.…”

Section: Discussionmentioning

confidence: 99%

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Isoprenaline, Ca2+ and the Na(+)‐K+ pump in guinea‐pig ventricular myocytes.

Gao

Mathias

Cohen

et al. 1992

The Journal of Physiology

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SUMMARY1. The whole-cell patch clamp technique was employed to study the effects of the ,f-agonist isoprenaline (ISO) on the Na+=K+ pump current, Ip, in acutely isolated ventricular myocytes from guinea-pig hearts. Propranolol, a ,l-adrenergic antagonist, was used to demonstrate that all of the effects of ISO, stimulatory or inhibitory, are mediated by fl-receptors. (Giles, Nakajima, Ono & Shibata, 1989; Duchatelle-Gourdon, Hartzell & Lagrutta, 1989) helps prevent action potential lengthening and allows an increase in heart rate even in the presence of increased calcium current. Further, fl-stimulation will compensate for the effects on Ip of either hypokalaemia or digitalis toxicity, and so reduce the expected rise in both [Na+]

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Section: Discussionmentioning

confidence: 99%

“…At reduced [Ca2+]i, ac,-stimulation has no effect. This has been interpreted as removal of Ca2+ inhibition by al-stimulation (Berthon, Capiod & Claret, 1985) evidence that favours such a physical mechanism over other alternatives such as a calcium-dependent regulatory protein or conformational changes in the pump causing a change in cycle rate.…”

Section: Resultsmentioning

confidence: 99%

Isoprenaline, Ca2+ and the Na(+)‐K+ pump in guinea‐pig ventricular myocytes.

Gao

Mathias

Cohen

et al. 1992

The Journal of Physiology

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“…Receptor-mediated rapid regulation of Na+/K+ ATPase has been proposed for arginine vasopressin (31,32), dopamine (33)(34)(35), and catecholamines (31,36,37), presumably through activation of intracellular signals. Studies in intact cells invoke protein kinase A (38)(39)(40), protein kinase C (33)(34)(35)41), and calcium/calmodulin-dependent protein kinases (37), but frequently these studies fail to account for concurrent changes in cytosolic concentrations of either sodium or ATP.…”

Section: Discussionmentioning

confidence: 99%

Short-term regulation of Na+/K+ adenosine triphosphatase by recombinant human serotonin 5-HT1A receptor expressed in HeLa cells.

Middleton¹,

Raymond²,

Whorton³

et al. 1990

J. Clin. Invest.

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Agonist occupancy of the cloned human serotonin (5-HT)1A receptor expressed in HeLa cells stimulates Na+/K+ ATPase activity as assessed by rubidium uptake. The purpose of the study was to determine which of the receptor-associated signaling mechanisms was responsible for this effect. 5-HT stimulated Na+/K+ ATPase 38% at 2 mM extracellular potassium, an effect characterized by a decrease in apparent Ko5 from 2.8±0.3 to 1.8±0.3 mM potassium without a significant change in apparent V,,,. The EC50 for the transport effect was -3 uM 5-HT. The response was pertussis toxin-sensitive but did not involve inhibition of adenylate cyclase, as stimulation of Na+/K+ ATPase by 5-HT was observed in the presence of excess dibutyryl cAMP. Protein kinase C was not required for the response since short-term incubation with the phorbol esters phorbol 12 myristate, 13 acetate (PMA) and phorbol 12,13-dibutyrate (PDBu) did not mimic the 5-HT effect. Moreover, 5-HT increased Na+/K+ ATPase activity after inactivation of protein kinase C by overnight incubation with PMA. 5-HT and the sesquiterpene lactone thapsigargin increased cytosolic calcium in this cell model, and the EC50 for 5-HT corresponded with that for stimulation of Na+/K+ ATPase. Both thapsigargin and A23187, a calcium ionophore, also increased Na+/K+ ATPase activity in a dose-responsive fashion. The response to 5-HT, thapsigargin, and A23187 was blocked by conditions that removed the cytosolic calcium response. By two-dimensional gel electrophoresis, we established evidence for a calcium-sensitive but protein kinase C-independent signaling pathway. We conclude that the 5-HTIA receptor, which we have previously shown to stimulate phosphate uptake via protein kinase C, stimulates Na+/K+ ATPase via a calcium-dependent mechanism. This provides evidence for regulation of two separate transport processes by a single receptor subtype via different signaling mechanisms. (J. Clin.

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“…It remains to be established whether in this system Ca2+ influx is dependent on either the counter-transport of some cation, or alternatively, the co-transport of some anion. Apart from stimulating the movement of Ca2+, the action of glucagon and Ca2+-mobilizing hormones has been associated with a stimulation of other ion transport processes such as Na+/K+-ATPase (Radominska-Pyrek et Berthon, Capiod & Claret, 1985;Lynch et al, 1986Lynch et al, , 1987 and Na+/H+-exchange (McGivan & Moule, 1987). However, the activation of these has not yet been shown to be obligatory for stimulation of Ca2+ influx.…”

Section: (6) Ion Fluxes Associated With Ca2+ Influxmentioning

confidence: 99%

Second Messengers and the Regulation of Ca 2+ Fluxes by Ca 2+ ‐mobilizing Agonists in Rat Liver

Altin

Bygrave

1988

Biological Reviews

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Summary Knowledge of the mechanism of action of Ca2+‐mobilizing agonists in liver has progressed considerably following the discovery that their interaction with specific receptors on the plasma membrane is accompanied by the hydrolysis of PIP2 and the generation of the second messengers diacylglycerol and IP3, for the activation of protein kinase C and the mobilization of intracellular Ca2+, respectively. Although the second messenger functions of diacylglycerol and IP3 in these actions seem well established, it is not yet clear how the agonists are able to regulate Ca2+ influx across the plasma membrane, an event which is crucial for those actions of the agonists which are dependent on the maintenance of an elevated level of cytosolic Ca2+, Whilst there is evidence for the existence of more than one pathway for Ca2+ influx in liver, it appears that in each instance the Ca2+ influx process is regulated differently to the Ca2+ influx through the volage‐sensitive Ca2+ channels that is known to occur in excitable tissues. At present it is not clear whether any of the Ca2+ influx pathways in liver is regulated by direct coupling to the agonist receptor mechanism on the outer surface of the plasma membrane, or whether the regulation involves the production of some second messenger(s). However, indirect evidence from a number of tissues appears to favour the involvement of both IP3 and IP4 in the regulation of Ca2+ influx. The mechanism by which IP3 and IP4 may regulate Ca2+ influx remains to be established, but it has been proposed that Ca2+ entry into the cell occurs through a pathway connecting the plasma membrane and the endoplasmic reticulum, following the release of intracellular Ca2+ from the lumen of the endoplasmic reticulum. Although it is not yet known whether glucagon (or cyclic AMP) activates the same pathway for Ca2+ influx as Ca2+‐mobilizing agonists, the marked potentiation by cyclic AMP of the Ca2+ influx induced by Ca2+‐mobilizing agonists has provided a powerful system with which to study the regulation of Ca2+ influx in liver. Whether this Ca2+ influx process occurs through some ion exchange mechanism (such as Ca2+/Na+ exchange) remains to be determined. Results from this study suggests that the Ca2+ influx is inhibited by neomycin, acidic pH, and a depolarization of the plasma membrane. The observation that cyclic AMP synergistically potentiates the influx of Ca2+ induced by Ca2+‐mobilizing agonists, that this influx appears to correlate with the reported ability of these agonists to induce PIP2 hydrolysis and accumulation of IP3, and that cyclic AMP synergistically potentiates the production of IP4 by vasopressin, are all consistent with the notion that IP3 and IP4 are involved in regulating Ca2+ influx. Whilst little is known about the Ca2+ transport process itself, these studies coupled with the recent finding that Ca2+ influx into the liver cell can occur through different pathways, seem set to lead to a better understanding of this important process in the near future.

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Effects of noradrenaline, vasopressin and angiotensin on the Na‐K pump in rat isolated liver cells

Cited by 25 publications

References 40 publications

Isoprenaline, Ca2+ and the Na(+)‐K+ pump in guinea‐pig ventricular myocytes.

Isoprenaline, Ca2+ and the Na(+)‐K+ pump in guinea‐pig ventricular myocytes.

Short-term regulation of Na+/K+ adenosine triphosphatase by recombinant human serotonin 5-HT1A receptor expressed in HeLa cells.

Second Messengers and the Regulation of Ca 2+ Fluxes by Ca 2+ ‐mobilizing Agonists in Rat Liver

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