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Intracellular Na+, K+ and Cl- activities in Acheta domesticus Malpighian tubules and the response to a diuretic kinin neuropeptide.
J Exp Biol. 2012 Aug 15; 215(Pt 16):2774-85.JE

Abstract

The mechanism of primary urine production and the activity of a diuretic kinin, Achdo-KII, were investigated in malpighian tubules of Acheta domesticus by measuring intracellular Na(+), K(+) and Cl(-) activities, basolateral membrane voltage (V(b)), fluid secretion and transepithelial ion transport. Calculated electrochemical gradients for K(+) and Cl(-) across the basolateral membrane show they are actively transported into principal cells, and basolateral Ba(2+)-sensitive K(+) channels do not contribute to net transepithelial K(+) transport and fluid secretion. A basolateral Cl(-) conductance was revealed after the blockade of K(+) channels with Ba(2+), and a current carried by the passive outward movement of Cl(-) accounts for the hyperpolarization of V(b) in response to Ba(2+). Ion uptake via Na(+)/K(+)/2Cl(-) cotransport, driven by the inwardly directed Na(+) electrochemical gradient, is thermodynamically feasible, and is consistent with the actions of bumetanide, which reduces fluid secretion and both Na(+) and K(+) transport. The Na(+) gradient is maintained by its extrusion across the apical membrane and by a basolateral ouabain-sensitive Na(+)/K(+)-ATPase. Achdo-KII has no significant effect on the intracellular ion activities or V(b). Electrochemical gradients across the apical membrane were estimated from previously published values for the levels of Na(+), K(+) and Cl(-) in the secreted fluid. The electrochemical gradient for Cl(-) favours passive movement into the lumen, but falls towards zero after stimulation by Achdo-KII. This coincides with a twofold increase in Cl(-) transport, which is attributed to the opening of an apical Cl(-) conductance, which depolarises the apical membrane voltage.

Authors+Show Affiliations

Birkbeck, University of London, London WC1E 7HX, UK. g.coast@bbk.ac.uk

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22837449

Citation

Coast, Geoffrey M.. "Intracellular Na+, K+ and Cl- Activities in Acheta Domesticus Malpighian Tubules and the Response to a Diuretic Kinin Neuropeptide." The Journal of Experimental Biology, vol. 215, no. Pt 16, 2012, pp. 2774-85.
Coast GM. Intracellular Na+, K+ and Cl- activities in Acheta domesticus Malpighian tubules and the response to a diuretic kinin neuropeptide. J Exp Biol. 2012;215(Pt 16):2774-85.
Coast, G. M. (2012). Intracellular Na+, K+ and Cl- activities in Acheta domesticus Malpighian tubules and the response to a diuretic kinin neuropeptide. The Journal of Experimental Biology, 215(Pt 16), 2774-85. https://doi.org/10.1242/jeb.072223
Coast GM. Intracellular Na+, K+ and Cl- Activities in Acheta Domesticus Malpighian Tubules and the Response to a Diuretic Kinin Neuropeptide. J Exp Biol. 2012 Aug 15;215(Pt 16):2774-85. PubMed PMID: 22837449.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intracellular Na+, K+ and Cl- activities in Acheta domesticus Malpighian tubules and the response to a diuretic kinin neuropeptide. A1 - Coast,Geoffrey M, PY - 2012/7/28/entrez PY - 2012/7/28/pubmed PY - 2012/12/10/medline SP - 2774 EP - 85 JF - The Journal of experimental biology JO - J Exp Biol VL - 215 IS - Pt 16 N2 - The mechanism of primary urine production and the activity of a diuretic kinin, Achdo-KII, were investigated in malpighian tubules of Acheta domesticus by measuring intracellular Na(+), K(+) and Cl(-) activities, basolateral membrane voltage (V(b)), fluid secretion and transepithelial ion transport. Calculated electrochemical gradients for K(+) and Cl(-) across the basolateral membrane show they are actively transported into principal cells, and basolateral Ba(2+)-sensitive K(+) channels do not contribute to net transepithelial K(+) transport and fluid secretion. A basolateral Cl(-) conductance was revealed after the blockade of K(+) channels with Ba(2+), and a current carried by the passive outward movement of Cl(-) accounts for the hyperpolarization of V(b) in response to Ba(2+). Ion uptake via Na(+)/K(+)/2Cl(-) cotransport, driven by the inwardly directed Na(+) electrochemical gradient, is thermodynamically feasible, and is consistent with the actions of bumetanide, which reduces fluid secretion and both Na(+) and K(+) transport. The Na(+) gradient is maintained by its extrusion across the apical membrane and by a basolateral ouabain-sensitive Na(+)/K(+)-ATPase. Achdo-KII has no significant effect on the intracellular ion activities or V(b). Electrochemical gradients across the apical membrane were estimated from previously published values for the levels of Na(+), K(+) and Cl(-) in the secreted fluid. The electrochemical gradient for Cl(-) favours passive movement into the lumen, but falls towards zero after stimulation by Achdo-KII. This coincides with a twofold increase in Cl(-) transport, which is attributed to the opening of an apical Cl(-) conductance, which depolarises the apical membrane voltage. SN - 1477-9145 UR - https://www.unboundmedicine.com/medline/citation/22837449/Intracellular_Na+_K+_and_Cl__activities_in_Acheta_domesticus_Malpighian_tubules_and_the_response_to_a_diuretic_kinin_neuropeptide_ L2 - http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=22837449 DB - PRIME DP - Unbound Medicine ER -