Linked Life Data

10650989

Source:http://linkedlifedata.com/resource/pubmed/id/10650989

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-2-28
pubmed:abstractText
The activation of cation channels in oocytes of Xenopus laevis by the marine poison maitotoxin (MTX) was monitored as membrane current (I(m)), conductance (Gm) and membrane surface area determined by continuous measurements of membrane capacitance (Cm). When MTX (25 pM) was added to the bathing solution there was an abrupt, large increase in inward membrane currents. Current/voltage relationships (I/V curves) were linear and suggested activation of voltage-independent non-selective cation channels (NSCC). MTX-induced Ca(2+)-sensitive currents were mainly carried by Na+ and were suppressed by low (0 mM) or high (40 mM) external Ca2+ concentrations and removal of Na+. Gadolinium (Gd3+, 10-500 microM) also had inhibitory effects, demonstrating the possible involvement of stretch-activated cation channels (SACC). In a high concentration (500 microM), amiloride substantially reduced the MTX-activated current while lower amiloride concentrations (50-100 microM) stimulated the current further. Continuous measurements of Cm revealed that MTX induced exocytotic delivery and functional insertion of new channel proteins into the plasma membrane, indicated by a Ca(2+)-dependent increase in membrane surface area by around 28%. From these data we conclude that MTX activates NSCC that require relatively high concentrations of amiloride to be blocked. Furthermore, MTX possibly stimulates activation of Gd(3+)- and Ca(2+)-sensitive mechanosensitive cation channels. Stimulation of these channels is achieved by exocytotic delivery and functional insertion of new channels into the plasma membrane in a pathway that depends on the presence of extracellular Ca2+.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
439
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
363-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10650989-Amiloride, pubmed-meshheading:10650989-Animals, pubmed-meshheading:10650989-Calcium, pubmed-meshheading:10650989-Cell Membrane, pubmed-meshheading:10650989-Colchicine, pubmed-meshheading:10650989-Diuretics, pubmed-meshheading:10650989-Electric Conductivity, pubmed-meshheading:10650989-Electric Stimulation, pubmed-meshheading:10650989-Electrophysiology, pubmed-meshheading:10650989-Exocytosis, pubmed-meshheading:10650989-Female, pubmed-meshheading:10650989-Gadolinium, pubmed-meshheading:10650989-Ion Channels, pubmed-meshheading:10650989-Marine Toxins, pubmed-meshheading:10650989-Membrane Potentials, pubmed-meshheading:10650989-Oocytes, pubmed-meshheading:10650989-Oxocins, pubmed-meshheading:10650989-Patch-Clamp Techniques, pubmed-meshheading:10650989-Sodium, pubmed-meshheading:10650989-Xenopus laevis
pubmed:year
2000
pubmed:articleTitle
Maitotoxin induces insertion of different ion channels into the Xenopus oocyte plasma membrane via Ca(2+)-stimulated exocytosis.
pubmed:affiliation
Laboratory of Physiology, K.U. Leuven, Belgium. Michael.Weber@med.kuleuven.ac.be
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't