Linked Life Data

19124225

Source:http://linkedlifedata.com/resource/pubmed/id/19124225

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
2009-2-3
pubmed:abstractText
SUMMARY: Zonisamide (ZNS) is a multi-target antiepileptic drug reported to be efficient in the treatment of both partial and generalized seizures, with T-type Ca(2+) channel blockade being one of its proposed mechanisms of action. In this study, we systematically investigated electrophysiological effects of ZNS on cloned human Ca(v)3.1-3.3 Ca(2+) channels in a heterologous HEK-293 expression system using whole cell patch-clamp technique. Concentration-response studies were performed in the range from 5 microM to 2mM for Ca(v)3.2 Ca(2+) channels exhibiting a 15.4-30.8% reduction of Ca(2+) influx within the maximum therapeutic plasma range (50-200 microM ZNS). The other T-type Ca(2+) channel entities, Ca(v)3.1 and Ca(v)3.3, were even less sensitive to ZNS. Both voltage- and concentration-dependence of inactivation kinetics remained unchanged for Ca(v)3.2 VGCC, whereas Ca(v)3.1 and Ca(v)3.3 exhibited minor, though significant reduction of inactivation-tau. Interestingly, ZNS block of Ca(v)3.2 VGCCs was not use-dependent and remained unaffected by changes in the holding potential. Steady-state inactivation studies did not display a significant shift in steady-state availability of Ca(v)3.2 channels at 100 microM ZNS (DeltaV(1/2)=3.1mV, p=0.071). Our studies indicate that ZNS is a moderate blocker of human Ca(v)3 T-type Ca(2+) channels with little or no effect on Ca(v)3.2 Ca(2+) channel inactivation kinetics, use- and state-dependence of blockade. These results suggest that T-type Ca(2+) channel inhibition only partially contributes to the anti-absence activity of ZNS antiepileptic drug.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1872-6844
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
83
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
224-34
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Zonisamide block of cloned human T-type voltage-gated calcium channels.
pubmed:affiliation
Institute of Neurophysiology, University of Cologne, Cologne, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't