Linked Life Data

12954859

Source:http://linkedlifedata.com/resource/pubmed/id/12954859

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2003-9-4
pubmed:abstractText
Protons are the most ubiquitous and very potent modulators of the biological systems. Hydrogen ions are known to modulate GABA(A) receptors (GABA(A)Rs), but the mechanism whereby these ions affect IPSCs and the gating of GABA(A)Rs is not clear. In the present study we examined the effect of protons on miniature IPSCs (mIPSCs) and found that hydrogen ions strongly affected both their amplitude and time course. To explore the underlying mechanisms with resolution adequate to the time scale of synaptic transmission, we recorded current responses to ultrafast GABA applications at various pH. These experiments revealed that the major effect of protons on GABA(A)R gating is a strong enhancement of desensitization and binding rates at increasing pH. This analysis also indicated that desensitization rate is the fastest ligand-independent transition in the GABA(A)R gating scheme. Although proton effects on the time course of mIPSCs and current responses to saturating [GABA] were similar, the pH dependencies of amplitudes were almost opposite. Our quantitative analysis, based on model simulations, indicated that this difference resulted from a much shorter receptor exposure to agonist in the case of mIPSCs. Modeling of IPSCs as current responses to brief exponentially decaying GABA applications was sufficient to reproduce correctly the pH dependence of mIPSCs, and optimal fit was obtained for peak [GABA] of 1.5-3 mm and a clearance time constant of 0.075-0.125 msec. Our analysis indicates that, for these parameters of GABA transient, in control conditions (pH 7.2) mIPSCs are not saturated.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
3
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7981-92
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Modulation of GABA(A) receptors by hydrogen ions reveals synaptic GABA transient and a crucial role of the desensitization process.
pubmed:affiliation
Department of Biophysics, Wroclaw Medical University, 50-368 Wroclaw, Poland. mozrzy@biofiz.am.wroc.pl
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't