Please use this identifier to cite or link to this item:
http://hdl.handle.net/1942/2461
Title: | K+ transport in Malpighian tubules of Tenebrio molitor L.: is a K-ATP channel involved? | Authors: | WIEHART, Ursula KLEIN, Georg STEELS, Paul Nicolson, SW VAN KERKHOVE, Emmy |
Issue Date: | 2003 | Publisher: | COMPANY OF BIOLOGISTS LTD | Source: | JOURNAL OF EXPERIMENTAL BIOLOGY, 206(6). p. 959-965 | Abstract: | The presence of ATP-regulated K+ (K-ATP) channels in Tenebrio molitor Malpighian tubules was investigated by examining the effect of glibenclamide on both fluid secretion and basolateral membrane potentials (V-bl). Glibenclamide, a KATP channel blocker, slowed fluid secretion of Tenebrio tubules. In low bath K+ concentration (5 mmol 1(-1)), glibenclamide either hyperpolarized or depolarized V-bl, resembling the effect seen with Ba2+. Subsequent addition of 6 mmol 1(-1) Ba2+ caused a further hyper- or depolarization of V-bl. In control Ringer (50 mmol 1(-1) KCl, 90 mmol 1(-1) NaCl), glibenclamide had no visible effect on V-bl. The effect of ouabain was investigated in low bath [K+] in the presence of Ba2+. V-bl responded by a small but significant hyperpolarization from -51 +/- 4 mV to -56 +/- 4 mV (n=16, P<0.001) in response to 1 mmol 1(-1) ouabain. Repeating the experiments in the presence of both glibenclamide and Ba2+ resulted in a depolarization of V-bl when ouabain was added. In low bath [K+] (high Na+), the Na+/K+-ATPase is expected to function at a high rate. In the presence of Ba2+, replacing Na+ by K+ rapidly depolarized V-bl, but this was followed by a repolarization. Repeating the experiments in the presence of glibenclamide markedly reduced the depolarizing effect and abolished the repolarization, with a gradual decrease in the sensitivity of V-bl to the surrounding [K+]. These results suggest the presence of K-ATP channels in the basolateral membrane. Glibenclamide had no visible effect on V-bl in high K+ or in the absence of Ba2+, indicating that other highly conductive K+ channels may mask the effect on K-ATP channels. This is the first demonstration of the presence of K-ATP channels in an insect epithelium. | Notes: | Limburgs Univ Ctr, Biomed CMK, Physiol Lab, B-3590 Diepenbeek, Belgium. Univ Pretoria, Dept Zool & Entomol, ZA-0002 Pretoria, South Africa.Van Kerkhove, E, Limburgs Univ Ctr, Biomed CMK, Physiol Lab, Univ Campus, B-3590 Diepenbeek, Belgium.emmy.vankerkhove@luc.ac.be | Keywords: | K+ transport; K-ATP channel; Malpighian tubules; Tenebrio molitor; glibenclamide; basolateral membrane potential; fluid secretion rate | Document URI: | http://hdl.handle.net/1942/2461 | ISSN: | 0022-0949 | e-ISSN: | 1477-9145 | DOI: | 10.1242/jeb.00201 | ISI #: | 000181805500003 | Category: | A1 | Type: | Journal Contribution | Validations: | ecoom 2004 |
Appears in Collections: | Research publications |
Show full item record
SCOPUSTM
Citations
12
checked on Sep 2, 2020
WEB OF SCIENCETM
Citations
16
checked on Oct 12, 2024
Page view(s)
78
checked on May 30, 2023
Google ScholarTM
Check
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.