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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2003-10-22
pubmed:abstractText
Local anesthetics and alcohols block impulse conduction in peripheral nerves by inhibiting Na(+) currents. In small peripheral nerve fibers, tetrodotoxin-resistant (TTX-r) Na(+) channels play an important role in impulse generation. We investigated the effects of lidocaine and the alcohol octanol on TTX-r Na(+) channels. Currents were recorded with the whole-cell patch-clamp method from enzymatically isolated rat dorsal root ganglion cells (data evaluation: nonlinear least-squares fitting). Lidocaine and octanol blocked the TTX-r Na(+) current in a reversible and concentration-dependent manner (50% inhibitory concentration values: 177 +/- 25 and 455 +/- 25 microM, respectively). Lidocaine additionally produced a strong use-dependent block. Both drugs showed a strong dynamic block (i.e., block developed during the time course of current activation and inactivation). Double-pulse protocols showed a slow dissociation of lidocaine from the channel during repolarization (time constant: 1763 +/- 63 ms; 300 microM). The dissociation of octanol was too quick to be distinguished from normal current repriming kinetics of 2.2 ms. Lidocaine and octanol acted noncompetitively in the Na(+) channel. Lidocaine and octanol have different blocking properties on the TTX-r Na(+) current and bind to different channel sites. IMPLICATIONS: Lidocaine and octanol have different inhibitory effects on the function of tetrodotoxin-resistant Na(+) channels in rat dorsal root ganglion cells, as well as noncompetitive modes of action, as investigated by the whole-cell patch-clamp method, and therefore are likely to have different binding sites on the channel.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0003-2999
pubmed:author
pubmed:issnType
Print
pubmed:volume
97
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1317-24
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Lidocaine and octanol have different modes of action at tetrodotoxin-resistant Na(+) channels of peripheral nerves.
pubmed:affiliation
Department of Anesthesiology and Intensive Care Medicine, University Hospital Charité Campus Mitte, Humboldt University, Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't