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http://hdl.handle.net/1942/4995
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DC Field | Value | Language |
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dc.contributor.author | LEYSSENS, Anne | - |
dc.contributor.author | Dijkstra, S. | - |
dc.contributor.author | VAN KERKHOVE, Emmy | - |
dc.contributor.author | STEELS, Paul | - |
dc.date.accessioned | 2007-12-20T15:54:38Z | - |
dc.date.available | 2007-12-20T15:54:38Z | - |
dc.date.issued | 1994 | - |
dc.identifier.citation | Journal of experimental biology, 195(1). p. 123-145 | - |
dc.identifier.uri | http://hdl.handle.net/1942/4995 | - |
dc.description.abstract | In the presence of 6 mmol l-1 Ba2+, known to block the K+ channels in the basal membrane, a rise in bath [K+] ([K+]bl) induced an increase in intracellular K+ concentration ([K+]i) similar in amount and in time course to that obtained in the absence of Ba2+. The presence of active and passive (other than through K+ channels) K+ uptake mechanisms across the basal membrane was investigated in different bath K+ concentrations. Dihydro-ouabain (10(-3) mol l-1), a blocker of the Na+/K(+)-ATPase, tested in low bath [K+], and Sch28080 (10(-4) mol l-1), a K+/H(+)-ATPase inhibitor, were without effect on fluid secretion. Dihydro-ouabain was also without effect on electrical potential differences either in the absence or in the presence of Ba2+. Vanadate (10(-3) mol l-1), in contrast, strongly reduced fluid secretion not only in control solution but also in high-K+, Na(+)-free medium and reduced the transepithelial and the apical membrane potential differences but not the basal membrane potential difference of [K+]i. Omitting Na+ from the bathing medium, replacing Cl- by Br- or applying bumetanide (10(-5) mol l-1) inhibited fluid secretion only in a low-K+ (10 mmol l-1) medium. In 51 mmol l-1 [K+]bl, omitting Na+ was without effect and 10(-4) mol l-1 bumetanide was needed to inhibit secretion. Replacing Cl- by Br- stimulated fluid secretion at this K+ concentration. Bumetanide (10(-4) mol l-1) had no effect in 113 mmol l-1 [K+]bl. Bumetanide (10(-4) mol l-1) in 51 mmol l-1 [K+]bl did not affect membrane potentials, did not lower [K+]i and did not affect the rise in [K+]i observed on an increase in [K+]bl. The results were summarized in a model proposing that K+ channels play a dominant role in high-K+ (113 mmol l-1) bathing medium. A K+/Cl- cotransporter may become more important in 51 mmol l-1 [K+]bl and a K+/Na+/2Cl- cotransporter may gain in importance in 10 mmol l-1 [K+]bl. Active mechanisms for K+ uptake across the basal membrane seem to play no detectable role in sustaining fluid secretion. The response to vanadate might be due to an effect on the apical electrogenic H+ pump. | - |
dc.language.iso | en | - |
dc.title | Mechanisms of K+ uptake across the basal membrane of malpighian tubules of Formica polyctena: the effect of ions and inhibitors | - |
dc.type | Journal Contribution | - |
dc.identifier.epage | 145 | - |
dc.identifier.issue | 1 | - |
dc.identifier.spage | 123 | - |
dc.identifier.volume | 195 | - |
dc.bibliographicCitation.oldjcat | - | |
dc.identifier.url | http://jeb.biologists.org/cgi/content/abstract/195/1/123 | - |
item.fulltext | No Fulltext | - |
item.fullcitation | LEYSSENS, Anne; Dijkstra, S.; VAN KERKHOVE, Emmy & STEELS, Paul (1994) Mechanisms of K+ uptake across the basal membrane of malpighian tubules of Formica polyctena: the effect of ions and inhibitors. In: Journal of experimental biology, 195(1). p. 123-145. | - |
item.accessRights | Closed Access | - |
item.contributor | LEYSSENS, Anne | - |
item.contributor | Dijkstra, S. | - |
item.contributor | VAN KERKHOVE, Emmy | - |
item.contributor | STEELS, Paul | - |
Appears in Collections: | Research publications |
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