Linked Life Data

1697218

Source:http://linkedlifedata.com/resource/pubmed/id/1697218

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1990-10-4
pubmed:abstractText
Following injection of rat striatal and cerebrellar mRNA, Xenopus oocytes were voltage clamped and current responses to the excitatory amino acid receptor agonist, kainate, were recorded. This nonspecific cationic current is carried principally by Na+ and K+ and reverses polarity at a membrane potential of approximately -5 mV. When the membrane potential was voltage clamped to -60 mV, bath-applied tetrabutylammonium (0.1-30 mM) produced a rapid, concentration dependent and reversible block of kainate-induced inward current with an IC50 of 1.3 mM. Tetraalkylammonium derivatives having shorter chains (methyl, ethyl, and propyl) were relatively ineffective blockers. Longer alkyl chain derivatives (pentyl, hexyl, and heptyl) were more potent than tetrabutylammonium but limited in their usefulness by their toxicity. The antagonism of kainate-induced current by tetrabutylammonium displayed apparently uncompetitive kinetics, in contrast with the competitive antagonism by gamma-D-glutamylaminomethylsulfonate. The block by tetrabutylammonium was strongly voltage dependent; an e-fold change in IC50 was observed for a 27 mV change in holding potential. Replacement of the Na+ in the medium with a more permeant cation (NH4+), a less permeant cation (tetramethylammonium), or an uncharged solute (mannitol) had little effect on the block of kainate-induced current by tetrabutylammonium. The rates of association and dissociation of tetrabutylammonium with the kainate receptor-channel are clearly rapid. These observations suggest that tetrabutylammonium enters and blocks the kainate receptor-associated cation selective channel. Tetrabutylammonium appears to traverse 80-90% of the membrane electrical field to reach a relatively low-affinity binding site that may simply be a narrowing of the channel.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0008-4212
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1069-78
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Tetrabutylammonium induces a voltage-dependent block of kainate current in Xenopus oocytes injected with rat brain mRNA.
pubmed:affiliation
Laboratoire de neurobiologie cellulaire et moléculaire, Centre national de la recherche scientifiqué, Gif-sur-Yvette, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't