Osmotic Modulation of the Ouabain-Sensitive (Na<sup>+</sup>+K<sup>+</sup>)ATPase from Malpighian Tubules of Rhodnius prolixus

Caruso‐Neves, Celso; Meyer-Fernandes, J.R.; Lopes, Anibal Gil

doi:10.1515/znc-1998-9-1021

Cited by 17 publications

(16 citation statements)

References 2 publications

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“…Downregulation of Na + /K + -ATPase activity, for example, will enhance elimination of Na + . It is worth noting that regulation of the activity of the Na + /K + -ATPase by protein kinase C has been reported in Malpighian tubule cells of R. prolixus (Caruso-Neves et al, 1998).…”

Section: The Effect Of Ba 2+ On Vbl: a Role For Basolateral CL -Channelsmentioning

confidence: 95%

Basolateral ion transport mechanisms during fluid secretion byDrosophilaMalpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Ianowski

O’Donnell

2004

Journal of Experimental Biology

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SUMMARY Mechanisms of ion transport during primary urine formation by the Malpighian tubule of Drosophila melanogaster were analyzed through measurements of fluid secretion rate, transepithelial ion flux, basolateral membrane potential (Vbl) and intracellular activities of K+ (aKi) and Cl–(aCli). Calculation of the electrochemical potentials for both ions permitted assessment of the possible contributions of K+ channels, Na+:K+:2Cl–cotransport, and K+:Cl– cotransport, to net transepithelial ion secretion across the basolateral membrane. The data show that passive movement of both K+ and Cl– from cell to bath is favoured across the basolateral membrane, indicating that both ions are actively transported into the cell. Contributions of basolateral K+ channels or K+:Cl– cotransporters to net transepithelial ion secretion can be ruled out. After prior exposure of tubules to ouabain, subsequent addition of bumetanide reduced fluid secretion rate, K+ flux and Na+ flux, indicating a role for a Na+:K+:2Cl– cotransporter in fluid secretion. Addition of the K+ channel blocker Ba2+ had no effect on aKi or aCli. Addition of Ba2+ unmasked a basolateral Cl– conductance and the hyperpolarization of Vbl in response to Ba2+ was Cl–-dependent. A new model for fluid secretion proposes that K+ and Cl– cross the basolateral membrane through a Na+-driven Na+:K+:2Cl–cotransporter and that most of the Na+ that enters the cells is returned to the bath through the Na+/K+-ATPase.

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Section: The Effect Of Ba 2+ On Vbl: a Role For Basolateral CL -Channelsmentioning

confidence: 95%

Basolateral ion transport mechanisms during fluid secretion byDrosophilaMalpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Ianowski

O’Donnell

2004

Journal of Experimental Biology

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“…Since different agonists and antagonist of purinergic receptors were used, it is less probable that the effect of adenosine on the (Na (Arenstein et al, 1995;Caruso-Neves et al, 1998). On the other hand, Maddrell and Overton (1988) (Riegel et al, 1998).…”

Section: Adenosine Subtype Receptormentioning

confidence: 99%

Adenosine modulates the (Na++K+)ATPase activity in Malpighian tubules isolated fromRhodnius prolixus

Caruso‐Neves

Monteiro

Oliveira

et al. 2000

Arch. Insect Biochem.

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The role of adenosine on regulation of the (Na++K+)ATPase activity present in the Malpighian tubules isolated from Rhodnius prolixus was investigated. Adenosine decreases the (Na++K+) ATPase specific activity by 88%, in a dose‐dependent manner, with maximal effect at a concentration of 10–9 M. This effect was mimicked by N6‐cyclohexyladenosine (CHA) at 10–8 M, an agonist for A1 adenosine receptor, and was reversed by 10–9 M 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPX), an antagonist for A1 adenosine receptor. On the other hand, 5′‐N‐ethyl‐carboxamide adenosine (NECA), an agonist for A2 adenosine receptor, used in the range of 10–9–10–5 M, did not change the (Na++K+)ATPase specific activity. In the same way, 10–8 M 3,7‐dimethyl‐1‐propargylxanthine (DMPX), an antagonist for A2 adenosine receptor, did not modify the inhibitory effect of adenosine. These data suggest that the inhibitory effect of adenosine on the (Na++K+)ATPase specific activity present in Malpighian tubules from Rhodnius prolixus is mediated by A1 adenosine receptor activation. Arch. Insect Biochem. Physiol. 43:72–77, 2000. © 2000 Wiley‐Liss, Inc.

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“…The addition of ouabain 1 mM did not change the RVI. Latter, we observed that hyperosmotic shock inhibited the (Na + +K + )ATPase activity but did not change the Na + -ATPase activity (Caruso-Neves et al 1998a, Figure 2). So it is possible to postulate that cell volume regulation during hyperosmotic shock involves the inhibition of the (Na + + K + )ATPase activity.…”

Section: Stress Conditionsmentioning

confidence: 83%

“…The presence of (Na + +K + )ATPase in the Malpighian tubule was confirmed by Lebovitz et al (1989) who cloned its α-subunit cDNA in the basolateral membrane of Malpighian tubule of Drosophila melanogaster. More recently, it was shown that a ouabainsensitive (Na + + K + )ATPase activity is present in the Malpighian tubule cells of Rhodnius prolixus (Grieco & Lopes 1997, Caruso-Neves et al 1998a.…”

Section: Sodium Pumpsmentioning

confidence: 99%

Sodium pumps in the Malpighian tubule of Rhodnius sp.

Caruso‐Neves

Lopes

2000

An. Acad. Bras. Ciênc.

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Malpighian tubule of Rhodnius sp. express two sodium pumps: the classical ouabain-sensitive (Na + + K + )ATPase and an ouabain-insensitive, furosemide-sensitive Na + -ATPase. In insects, 5-hydroxitryptamine is a diuretic hormone released during meals. It inhibits the (Na + + K + )ATPase and Na + -ATPase activities indicating that these enzymes are involved in fluid secretion. Furthermore, in Rhodnius neglectus, proximal cells of Malpighian tubule exposed to hyperosmotic medium, regulate their volume through a mechanism called regulatory volume increase. This regulatory response involves inhibition of the (Na + + K + )ATPase activity that could lead to accumulation of active osmotic solute inside the cell, influx of water and return to the normal cell volume. Adenosine, a compound produced in stress conditions, also inhibits the (Na + + K + )ATPase activity. Taken together these data indicate that (Na + + K + )ATPase is a target of the regulatory mechanisms of water and ions transport responsible for homeostasis in Rhodnius sp.

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Osmotic Modulation of the Ouabain-Sensitive (Na⁺+K⁺)ATPase from Malpighian Tubules of Rhodnius prolixus

Cited by 17 publications

References 2 publications

Basolateral ion transport mechanisms during fluid secretion byDrosophilaMalpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Basolateral ion transport mechanisms during fluid secretion byDrosophilaMalpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Adenosine modulates the (Na++K+)ATPase activity in Malpighian tubules isolated fromRhodnius prolixus

Sodium pumps in the Malpighian tubule of Rhodnius sp.

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Osmotic Modulation of the Ouabain-Sensitive (Na++K+)ATPase from Malpighian Tubules of Rhodnius prolixus

Cited by 17 publications

References 2 publications

Basolateral ion transport mechanisms during fluid secretion byDrosophilaMalpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Basolateral ion transport mechanisms during fluid secretion byDrosophilaMalpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Adenosine modulates the (Na++K+)ATPase activity in Malpighian tubules isolated fromRhodnius prolixus

Sodium pumps in the Malpighian tubule of Rhodnius sp.

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Osmotic Modulation of the Ouabain-Sensitive (Na⁺+K⁺)ATPase from Malpighian Tubules of Rhodnius prolixus