Ion channel activity from the midgut brush-border membrane of gypsy moth (Lymantria dispar) larvae | Health & Environmental Research Online (HERO)

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Citation
Tags

HERO ID

647923

Reference Type

Journal Article

Title

Ion channel activity from the midgut brush-border membrane of gypsy moth (Lymantria dispar) larvae

Author(s)

Peyronnet, O; Vachon, V; Schwartz, JL; Laprade, R

Year

2000

Is Peer Reviewed?

Yes

Journal

Journal of Experimental Biology
ISSN: 0022-0949
EISSN: 1477-9145

Volume

203 Pt 12

Issue

Page Numbers

1835-1844

Web of Science Id

WOS:000087938800007

URL

http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10821741
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Abstract

Ion channels from the midgut apical membrane of gypsy moth (Lymantria dispar) larvae were studied following mechanical fusion of brush-border membrane vesicles with planar phospholipid bilayer membranes. In symmetrical 300 mmol l(-)(1) KCl (pH 9.0), nine different channels with conductances ranging from 27 to 795 pS and linear current/voltage relationships were resolved. In the presence of a KCl gradient across the bilayer (450 mmol l(-)(1 )cis/150 mmol l(-)(1 )trans), 11 different conductance levels ranging from 16 to 850 pS were detected. The channels were slightly cationic: the zero-current reversal potential was shifted by -5 mV to -21 mV compared with symmetrical KCl conditions, corresponding to p(K)/p(Cl) permeability ratios of 1.5-8.0. Most channels were neither voltage-dependent nor Ca(2+)-sensitive and displayed complex gating kinetics. Addition of Ba(2+) or Cs(+) to both sides of the bilayer had little effect on channel activity, but fewer distinct channels were observed when KCl was replaced by potassium gluconate, suggesting an effect of Cl(-) on channel activity. A reduced number of channels was also detected when KCl was replaced by N-methyl- d-glucamine-HCl. Under asymmetrical N-methyl-d-glucamine-HCl conditions, only anionic channels were observed. They exhibited current rectification (35 pS at negative voltages and 81 pS at positive voltages) and were strongly voltage-dependent.

Keywords

Animal; Anions; Barium; pharmacology; Cesium; Electric Conductivity; Gluconates; Intestines; Ion Channels; physiology; Lipid Bilayers; metabolism; Meglumine; Membrane Fusion; Microvilli; Moths; Potassium Chloride; Support; Non-U.S.Gov't